THE SPREAD OF POTATO BLIGHT IN EUROPE IN 1845-6
AND THE ACCOMPANYING WIND AND WEATHER PAI"IERNS
Austin Bourke and Hubert Lamb
,:;:" ... ~'", '~ .. 9 Published in 1993 by the Meteorological Service: Glasnevin Hill. Dublin 9
By kind permission of the Commission of the European Communities
Copyright © the authors 1993 All rights reserved
Cover: Famine Funeral at Skibbereen ( from Illustrated London News. January 30. 1847) (archives of the National library) and picture of blighted potato foliage on background synoptic map ofJuly 31. 1846 (see Fig. 10).
Famine letter on page 12: Original letter from 1847 reproduce:d in an article by R. McKay. late Professor of Plant Pathology. UeD. as published in Department of Agriculture Journal 1953-54
Text layout and design by Tom Keane. Meteorological Service:
ISBN 0 9521232 0 7 PREFACE
The first R&D programme in the field of climatology. which was adopted by the Council of the European Communities in ) 979. led to the promotion of 5) international research projects in different aspects of -- understanding climate and of man-climate interactions. Under the terms of Contract CLI 065 UK(H). Professor H.H. Lamb (Norwich) and Dr Austin Bourke (Dublin) undertook a study of the biorneteorological background to the historic epidemic of potato blight which raged in Western Europe in the years) 845-6 and which culminated in the great Irish famine. Apart from its historical interest. the study has implications for the present day epidemiology of plant diseases of food crops. particularly in the Third World. The report is published in its present form by kind permission of the Commission of the European Communities. and the Director of the Irish Meteorological Service.
iii ACKNOWLEDGEMENTS
The authors wish [0 record their gratitude to a Zurich. for the Basle and Geneva observations; number of individuals who took great trouble Dr Vklav Richter. Director of the Czech in identifYing relevant meteorological data in Hydrometeorological Institute. Prague. for the their archives and institutions which supplied gift of the long series of carefully homogeniud copies of their data free of charge, notably: daily instrument measurements from Prague (Klementinum) 1775-1975; Professor Dr Dr Hlynur Sigtryggsson. Director of the Iceland Weather Bureau. who supplied the Godlewski. Director of the Institute of Stykkisholmur observations; SjMn Meteorology and Water Management. Warsaw. for the provision of observation data from that Kristjinsd6ttir. Reykjavik. who obtained and translated the Eyjafjordur data in a period of city and translation of the key words; to great personal inconvenience to herself; Dr Professor Manuel Puigcerv iv ------ CONTENTS Page List of Maps and Diagrams ____... ______. __ VI Chapter I Introduction I Chapter 2 The Potato Crop in Europe _____._.__ 3 Chapter 3 The Meteorology of Potato Blight __ .____ 7 Chapter 4 The Weather in the Years Concerned 13 Chapter 5 Potato Blight in Europe in 1845 31 Chapter 6 Potato Blight in Europe in 1846 ______41 Chapter 7 Summary of Conclusions 49 References --_. ------___ 51 Appendix List of Meteorological Observation Sites and Data Sources _. _____._. ___ .______54 Index 64 v LIST OF MAPS AND DIAGRAMS Fig. 1 Approximate extent of potato blight attacks in the USA and Canada in the years 1843-45 (after Stevens. 1933). Fig. 2 Air trajectory for the transport of foot-and-mouth disease from Brittany to the UK on 10 March 1981 (after Donaldson d a~ 1982). Fig. 3 Anomalies of the air temperatures prevailing in (a) June. (b) July. (e) August. (d) Septembc:r. 1845-i.e. departures in °C of the monthly mean temperature from the 1851-1950 average. Fig. 4 Anomalies of the air temperatures prevailing in (a) June. (b) July. (c) August. (d) Septembc:r. 1846-i.e. departures in °C of the monthly mean temperature from the 1851-1950 average. Fig. 5 Anomalies of the mean air temperatures for the (a) summer of 1845. (b) winter of 1845-46. (c) summer of 1846 and (d) winter of 1846- 47. i.e. summer departures in °C of the mean temperature of the period June. July and August and winter departures of the period Deccmbc:r. January and February from the 1851-1950 average. Fig. 6 Mean barometric pressure at sea level in hectoPascals in July 1845. Fig. 7 Mean barometric pressure at sea level in hectoPascals in July 1846. Fig. 8 Synoptic weather map: situation at 14h. on 23 July 1845. Fig. 9 Synoptic weather map: situation at 14h. on 17 Septembc:r 1845. Fig. 10 Synoptic weather map: situation at 14h. on 31 July 1846. Fig. 11 Dates in 1845 when progress of blight was so generally noticeable as to cause comment and alarm. Fig. 12 Blight weather spells and their effective duration (in hours) in seasons with early development of potato blight in the Netherlands. Belgium and Chile. Fig. 13 Blight weather spells and their effective duration (in hours) in Belgium and Ireland during the potato growing seasons 1845-1847. Fig. 14 Approximate distribution of potato blight damage in western Europe in 1846. Fig. 15 Population changes after 1821 in Ireland and in England - Wales. VI CHAPTER 1 INTRODUCTION I.l Subject agricultural production which merits a full This report is concerned with a quantitative review by a competent authority (Whyte. 1963). biometeorological study of the interaction of No such review has yet been undertaken. weather and plant disease in the historic potato Meanwhile certain trends in agricultural blight epidemic of 1845-6 in western Europe. practice have tended. if anything. to increase Dr Austin Bourke (Dublin). author of a the risk of sudden sharp crop losses due to number of previous studies of potato blight and disease or pest. despite the development of the Irish disaster in the eighteen-forties. resistant plant varieties and of chemical and extended his srudies in this report with the aid other counter-measures. of a much more comprehensive collection of Paradoxically the risk of serious attacks by meteorological data from allover Europe than plant parasites has tended to increase by reason was previously available. Professor Hubert of the very practices designed to promote food Lamb (Norwich) reports in Chapter 4 on the production: rapid and widespread adoption of data collected and on the reconstruction of the new cuhivars. more intensive cropping, the meteorological situations in the 1840s which growing of more than one crop per year. the were part of the background to the disaster. wide use of irrigation and increased fertilizer use. The phytosanitary dangers of devoting 1.2 Background ever greater areas of land to a single crop and Concern has been growing in recent years as to often to a single variety (monoculrure) in place how future climatic change might affect of the diversified patterns of traditional farming agriculrural production. A realistic assessment have already begun to show themselves in of this question needs to take account not different parts of the world. merely of how the changed environment would affect the growth and wellbeing of plants and 1.3 Objective animals. but also of the repercussions of an An example of a most devastating sudden altered climate on the distribution and disease attack on a food crop is the historic virulence of a wide variety of diseases and pests epidemic of potato blight which ravaged much which can damage farm crops and livestock. of western Europe in 1845-6. The objective of Nearly thirty years ago Dr R 0 Whyte of FAO this report is to carty out a detailed case srudy of drew attention to this problem as an aspect of the 1845-6 epidemic. covering its first impact great economic significance to land use and in the Low Countries and its subsequent spread. 1 Potato Blight in Europe in 1845-6 and teI.ating these to the accompanying weather monoculture as in the famine situations of the and wind patterns. The research sought to past). occurred in the Netherlands in the 1950s throw light on the factors that favoured the with a newly developed strain of wheat. This rapid spread of the potato disease through wheat. known as Heines VII. had been hailed as western Europe in the first year of irs appearance a much prized product of scientific plant (1845). on the contribution which the wind breeding. developed for irs resistance to the then borne spread of fungal spores made to the known forms of yellow rust disease. Three years propagation of the disease over fairly lengthy after irs introduction in 1952. 80 per cent of distances. and on the contribution that the wheat sown in Holland was Heines VII. weather conditions made to irs life-cycle in the Then a new variety of yellow rust appeared and years 184 5 and 1846. It is hoped thar the destroyed over two-thirds of the winter wheat detailed analysis of the 1845-6 analogue. with sown in that country for the 1956 harvest. its profound ~conomic and social consequences, Happily. in this case there was enough diversity may help towa,rds the interpretation and in the Dutch agricultural economy to withstand countering of similar plant disease epidemics in the blow. Such events could be much more the future in whatever part of the world they devastating in the Third World. strike. The impact of unfavourable weather conditions on a community. whether by direct 1.4 Structure of the Report action or by limiting food supplies. depends to a Chapters 2 and 3 of the report are devoted to a major degree on me socio-cconomic conditions broad survey of the emergence of potato blight which prevail. In this respect the situation in in the 1840s. of the way the disease operates to Ireland on the eve of the potato blight disaster. damage the potato crop. and of how irs seasonal with a swollen population very largely course is affected by weather conditions. dependant for survival on a single vulnerable Chapter 4 describes materials and methods food crop. was precarious in the extreme. available for revealing the meteorological An example of how even a modern European characteristics of those years and the development economy may prove vulnerable to risks of the weather in the seasons concerned. while somewhat analogous to the Irish experience of Chapters 5 and 6 deal with the European potato blight epidemics of 1845 and 1846 respectively. the potato disease in the 1840s. particul ..ly where rationalization in agriculture has The findings of the study are summarised in eliminated diversity (Le. has tended to restore Chapter 7. 2 CHAPTER 2 THE POTATO CROP IN EUROPE 2.1 The Potato Crop in Europe and the 2.2 The Potato Crop and its Earlier Emergence of a New Disease Problems The first manifestation of blight in the Aftor the potato was first brought by the European potato crop in 1845 was greeted with Spaniards from South America to Europe about unprecedented panic and consternation. No the middle of the sixteenth century. it remained previously known crop disease had carried out for many years free of serious diseases. It its destructive work with such terrifYing speed showed itself to be a crop of remarkable and completeness. The superstitious dread of sturdiness and vigour of growth. more typical the common people. faced by a disease so perhaps of a weed than of a cultivated plant; in inexplicably different in its course from the those early years it grew outstandingly well in slowacting and localised ailments which had wet seasons when the failure of the wheat and previously taken partial toll of their food crops, other grain crops led to a shortage of food. was intensified by the confusion and discord This advantage loomed particularly large in the among the learned who were hopelessly divided darnp climate of Ireland where the potato soon about the cause of the new disease, how it came into widespread cultivation; and. from might be combatted. whence it had come. and Ireland. its reputation "as a bulwark against the reason for its sudden emergence from starvation· in bad seasons Jed to irs previous obscurity. unless perhaps it had arisen introduction. often under the narne of the 'Irish by 'spontaneous generation' (Bourke. 1991). potato', into other countries. It was not initially realised in Europe that With the rapidly growing populariry of the potato blight had made its appearance two years potato. things began slowly but surely to change earlier in North America. close to the great for the worse. The more widely a particular seapom of the east coast of the United States. crop is grown, the more vulnerable it becomes and had spread with impressive speed to almost to disease. Gradually the potato began to suffer the entire area in which the disease is a serious from specific maladies, apart from frost dWlage problem for today's American potato growers. and simple water.logging in poorly drained Fig. I is based mainly on the work of Stevens soils. The more important developments were (I933). supplemented by a limited amount of virus disease ('the curl') and dry rot ('the taint'). extra information on the arrival of the disease in ailments which tended to be a bigger problem Canada (Bourke. 1%9). in dry seasons and on the continental mainland. 3 POlaco Blighl in Europe in 1845-6 1844 Fig. 1 Approximate exlent of poUto blight atucks in the USA and Canada in the years 1843-45 (after Stcvcns) Despile Ihese ulher worrying devdopmems. grown). the repulalion of Ihe po,alO as the mosl rdiable In favour of a South American birthplace is of European food crops. and the solid bollom the fact Ihat a number of other major plant line of defence againS! famine. laS!ed righl diseases have been shown 10 have originated in down [0 1845 when Ihe bubble bursl with a Ihe same areas as Iheir hoS( plan IS. vengeance. Furthermore. a leady means of Iransport of diseased POIaIOCS direct from Peru 10 the USA and Europe in Ihe early 1840s was provided by 2.3.1 Whence came the Blight Fungus a l.. ge f1eel of cargo boalS which was engaged in Nearly one hundred and fif!), years after POlaCO calering for Ihe guano boom of those years. blight made its firs! appearance. Ihere is Slill no agrcemenl amongS! the scholarly as 10 where Ihe cradle of the causal fungus was localed. wi,h 2.3.2 A Potato Importation from the Ihe main body of opinion divided belween Americas Mexico and Ihe Andean homdand of the polatO It seems moS! probable that blighl came from (apart from Ihe Slubborn few who cling 10 the America 10 Europe in a cargo of pOlatoes Iheory that the fungus had long been preseO officially imponed inlo Belgium in an effort 10 wherever the potalO was grown. bUI had bring new vigour imo an ailing crop (Bourson. somehow managed previously 10 keep a low 1845). AI the opening of the provincial council profile no ma((er how favourable Ihe weather of Wesl Flanders on 4 July 1843 the Governor had been or how susceplible Ihe POlaCO varieties referred 10 Ihe food problems facing the poor 4 The Poraro Crop in Europe because of rhe 'degenerarion' of rhe poram. due World War" the urgent need ro grow potaroes mainly ro virus disease and dry ror. and in Kenya ro feed allied troops led ro rhe proposed rhar recourse be had ro America. land importation and planring in 1941 of a large of origin of rhe poraro. in order m renew and consignment of seed poratoes from the UK. improve rhe species. The original idea of The season of introduction was exceprionally importing wild poumes was soon dropped favourable for the onset and developmenr of when expert advice poinred our rhar rhese could poraro blight. and rhe disease spread wirh nor be developed into a useful crop for some devastaring energy rhroughour Kenya and later years afrer introducrion. Insread. trials of invaded Tanzania. Uganda and Zaire (Cox and commercial potaro varieries from difTerent Large. 1960). countries were undertaken at rhe experimental Diseased rubers are also rhe means by which farm ar Cureghem. and when two parricularly blighr is carried over rhrough rhe winrer from promising culrivars had been selecred. ir was one planting season to the next, either as announced rhat large quantiries of rhese infected seed which goes underected ar plan ring varieries had been ordered from abroad and time. or as rubers discarded ar harvest rime and would. it was hoped. arrive shortly - presumably surviving over the winter, or as groundkeepers. in time for rhe 1844 growing season. According to Bourson (1845). rhe 1844 potaro It is convenient ro consider rhe damage caused crop ar Cureghem grew very well. but a number by potato blighr under rhree separare headings: of rhe harvesred tubers developed black spors and rotted in storage. We know rhar poraroes from Peru. and. in 2.4.1 Foliage Blight panicuIar, varieties named 'PC'ruvienne', 'Lima' The disease can reduce the growing season of and 'Cordilieres' were among rhe first crops the crop by killing the foliage before the normal which were badly attacked by blight in 1845. harvesr dare is reached. The earlier the topS are No doubt. however. rhe Cureghem imports also effectively dead. rhe lower will be the yield. The included po tames from rhe Unired Srares. so broad growth pattern of maincrop poratoes. rhat it is not possible ro point rhe finger of guilr which require a six-month season from planting wirh conviction ro imports from any particular ro full harvest. may be summarised as follows. region. In any case. once blighr had established The planrs emerge above rhe ground. on irself in North America. which had constant sea average. about one monrh after planring. traffic across rhe Atlanric and a free exchange of During this period. and for a further period of poraro varieties with Europe. ir could nor be one-and-a-half monrhs. rhe entire energy of the very long before rhe disease found irs way to the plants is devored to the production of roors and Old World. haulms. Tuber formation begins slowly in the second fortnight of the third monrh when approximarely 15 per cenr of rhe porential final crop weight is produced. In ,he following six 2.4. How Blight Damages the Potato fortnights. up to full harvest time. the successive Crop addirions of ruber weight are. in round figures. The modus operandi of potaro blight is no 15 per cent. 20 per cenr. 20 per cent. 15 per longer rhe mysrery it was on irs firsr appearance. cent. 10 per cent and 5 per cenr. Thus. if the The long-distance spread of rhe disease inro planting dare of maincrop potatoes is taken as 1 districts where it had formerly been unknown is April. with an expected harvest dare of the end normally brought abour by the unwitting of Seprember. destruction of rhe raps by mid inrroduction of infected rubers. Thus. early in July would lead to a crop loss of70 per cent. by 5 Poroto Blight in Europe in 1845-6 I August of 50 per cent. by mid-August of 30 2.5 Rotting of Tubers in Storage due to per cent. This is. of course. a generalised Blight picture of potato crop growth which. in a The post-harvest rotting of tubers in storage particular season. needs adjustment to take due to blight came as a complete shock to the account of changes in the date of planting. and growers in 1845 who thought thac the full of any checks to growth caused by drought or extent of their losses had been made plain at other factors. This being allowed for. the digging time. It was feared thac the entire figures teflect surprisingly well the extent of harvest would mdt away. They were unaware yield losses in different seasons corresponding that the disease did not normally spread in with the dates of haulm destruction. storage from infected to sound tubers; thus the ultimate losses in many cases were substantially less than had been feared when rotting in 2.4_2 Tuber Blight Prior to Harvesting storage was first noted. Spores of the disease formed on the foliage may be washed down by rains into the earth where they can infect the tubers in the ground. The 2.6 The Extent of Carry-Over of extent to which this occurs depends on a Infection from One Season to the number of factors. the main one being the Next frequency of heavy rains when the spores of the disease are in active production. Often a long. A factor of some importance affecting the slow attack of foliage blight in which seasonal onset and development of potato sporulation continues untiliatC' in the season blight is the amount of inoculum present early will give rise to more tuber blight than a rapid in the season. which in turn depends on the and spectacular early-season destruction of the degree of carry-over of infection from the haulms. which indeed leads to a major drop in previous year. yield. but one which is often made up of mainly Over a hundred years ago. Jensen (1887) healthy potatoes_ remarked on the tendency for the disease to make its appearance relatively late and relatively early in successive years. This could reflect the trend. discussed in the previous section. for late season blight to contribute to a higher level of 2.4_3 Tuber Blight at Harvest Time tuber infection in the seed used in the Direct infection of the tubers when they are following season. dug out at harvest time can ~ a serious source Another factor which can contribute to a of loss in some years. It does not take place if high carry-over of infection is the lack of the foliage has died. due to disease or natural awareness of the importance of hygiene. causes. sufficiently in advance of harvest date to particularly in areas where the disease is new. avoid survival of the blight fungus in the surface leading to widespread abandoning of diseased soil. It is most likely to occur in the case of potatoes in the fields (as happened. for example. late-season foliage blight attacks. when the in Chile in 1950-51). A mild winter can plants are still green and producing spores at the contribute to the survival of discarded tubers time of digging. Destruction or removal of the and of groundkeepers. and to early sprouting of haulms well in advance of harvesting destroys infected tubers in cullpiles. this source of infection. 6 CHAPTER 3 THE METEOROLOGY OF POTATO BLIGHT 3.1 Weather and Blight principles. and to try to incorporate into a new The fact thac the seasonal weather plays a system the essential features of a comprehensive dominant role in the development of an series of laboratory determinations (Crosier. epidemic of potato blight was recognised soon 1934) of the relationship between weather after its first appearance in Europe. At that time condidons and successive stages in the the fungal cause of the disease was recognised development of blight on the foliage of potaro only by a handful of scientists: hence the plants. The 'Irish Rules'. as developed in 1949. weather's function in conrrolling the life cycle were designed for use with hourly observations of the fungus was equally unrecognised. The made at standard meteorological stations. and consensus of opinion in 1845 considered that required as an absolute minimum: blight was a direct consequence of weather conditions alone (Graham. 1847). It was not until the 1860's that the fact that a) a period of at least 12 hours during which blight is caused by a fungus (Phytophthora the relative humidity of the air does not inftstans) won general acceptance, and not fall below 90 per cent nor the air until the turn of the century that the use of temperarure below 10.ODC. (Conditions fungicides against the disease was introduced. which permit the formation of disease The first empirical attempt to develop a spores outside the leaves of already infected practical model of the meteorological conditions plants. to be carried by air currents to new which favour the blight fungus. which might be sites) used to advise growers on what dates to apply fungicides. was carried out in the Netherlands at b) free water on the po taro leaves for a the end of the First World War (Bourke. 1955). subsequent period of at least four hours. (A Building on the Dutch foundation. a simple condition which permits any newly criterion, the S 7 Potato Blight in Europe in 1845-6 a blight period of x hours constitutes an of the disease. If the ncccss;uy meteorological 'effective period' of x-II hours. Two conditions arc repeated. a second and naturally consecutive blight periods sepamed by a gap of more general infection will take place. The less than six hours arc: combined (0 effect of each generation on the spread of the calculate the effective duration. i.e. only one disease will depend on the amount of the deduction of II hours is made from the inoculum initially present. and on the duration total length of the consecutive periods. of the favourable conditions. Experience in Europe suggests that. where a crop is not Different blight periods and different seasons are compared in terms of the total numbers of subject to direct infection from a neighbouring Effective Blight Hours (EBH) calculated in this early crop in which the disease is already raging. way. between three and five generations may be needed to develop the disease to the level at In practice. whenever condition (a) has been which it can be noticed readily in the crop. met. it is rarely that condition (b) will not \;e· found to follow automatically: rain or drizzle frequently accompanies periods of high humidity. Nature so organises itself that spores 3.2 Weather Patterns. Airmass Analysis will rarely be discharged into a hostile and Plant Disease environment. An essential adjunct to plant disease forecasting in Ireland from its early stages has been the The Irish Rules. having been tried synoptic weather chart (Bourke. 1957). It was experimentally during the 1950 and 1951 crop soon confirmed that the conditions favourable seasons. were adopted as the basis for an Irish to potato blight do not come together by blind blight forecasting system in 1952. No chance. but arc associated with particular types modification has been found necessaty during of rc:cucn:nt synoptic weather situations. Those their successful operation over a period of forty which normally give the most significant years. They have given satisfactoty results also periods of blight weather in western Europe fall in Chile and Tasmania. The relative humidity into two broad catcgories: criterion of 90 per cent has been adopted in the UK for use in the blight warning procedures which replaced the Beaumont system in 1975. Accordingly. the Irish Rules 3.2.1 Open warm sectors of maritime have been selected with some confidence for use tropical air, particularly where two in the present study to analyse the blight or more waves follow in sequence potential of different weather seasons. Maritime tropical air. as it reaches northwest Europe in summer. normally gives ideal A spell of blight weather permits the fungus conditions for the development of blight. to undergo the three consecutive stages of especially close to the wave centres: high sporulation. germination and infection-a humidity. overcast skies with drizzle. wet fog or sequence which is followed by a period of rain, and temperatures normally of the order of incubation. i.e. the interval which elapses l2°C - 16°C. By its very nature. this situation between infection and the first appearance of is essentially maritime. and often the associated damage. The length of the period depends pressure systems sweep northeastwards. mainly on temperature. but is normally between affecting mainly the coastal regions. In some betwccn thrcc and five days. seasons, however. the: invasion of maritime The four basic processes - sporulation. tropical air plunges eastwards to take large parts germination. infection and incubation .. of continental Europe into its sphere of complete one cycle or generation in the spread influence:. 8 The Meteorology of Potato Blight 3.2.2 Stagnant or slow-moving, shallow temperature has been strikingly illustrated in depressions giving long periods of Iceland where potatoes form an important food wet overcast weather crop despite low summer temperatures and a comparatively short growing season. In their The shallow. stagnant "puddle low" is primarily pioneer study of POtato blight epidemics a continental rather than a maritime throughout the world. Cox and Large (I 960) phenomenon. although its effects can spill over remarked that "the occurrence of potato blight wesrwards from the European mainland to East in iceland is of special interest as the and South·east England. and very occasionally temperature conditions are here at the lower to Ireland. The temperature level in this limit for any epidemic development of the situation in summer in north-west Europe is disease"' . almost always favourable to me disease. and the persistent rainfall associated with convergence The Icelandic blight records showed that. in maintains a high level of air humidity. 111- favourable conditions of air humidity. the defined quasi-stationary fronts are frequently disease damaged the crop in those years when associated with me stagnant area of low pressure the mean daily temperature in July and August which may show more than one shallow centre. reached the 12° - 13°C level. but appeared to be The air is often unstable and. particularly in the inhibited when these temperatures ranged about later stages of the puddle low. widespread 10-1\ °C. In the period 1936 - 1959. during outbreaks of rhu-nderstorms are not uncommon. which blight built up to become a serious and recurrent problem in Iceland, there were six years of severe blight; in those six years mean air temperatures were consistently higher in July (average 12.3°C. as against I 1.2"C). and in 3.3 The Importance of Temperature August (average 11.7°C. as against 10.7°C) man In the various models for blight weather which they were in the years oflinle or no disease. have been developed over the years for use in Nor was this the whole story. Table 1 shows western Europe. the specified minimum ,he mean monthly air temperature in Reykjavik temperature level has remained unaltered at for ,he momhs of July and August for each 10.0°C. The importance of the minimum decade of ,he present century up to 1980. TABLE 1: Mean Monthly Air Temperature (0C) duringJulyand August in Reykjavik in successive decades. 1901 - 80 July August °C 1901 - 10 11.4 10.3 1911 - 20 11.6 11.0 Inl - 30 Il.l 10.4 1931 - 40 12.0 11.3 1941- 50 11.5 Il.l 1951 - 60 11.2 10.7 1961 -70 10.6 10.5 1971-80 10.6 10.2 9 Potato Blight in Europe in 1845·6 Concurrent with the rise of temperature and of the black rust of wheat. Pu&cinia graminis. blight impact in Iceland. there occurred a Hogg (1970) describes the wind trajectories gradual rise of air temperature early in the which have been found to bring black rust spores century to a clear plateau of warmth in the from continental Europe to England. a country 1930·s. followed by the onset of cooling. which is not subject to the disease ucept in gradual at first but sharper since 1960. to a levd growing seasons when inoculum is imported on in the 1970's represented by lower values than the wind from abroad. Each case of uredospore any recorded for the earlier decades of this (rust spore) introduction was shown to involve a century. Simultaneously with the temperature precise synchronisation of spore liberation and fall. the impact of blight in Iceland has gradually deposition with the movement of weather died down. so that in the late 70's the disease systems and the speed of the winds within them. has been hard to detect. It would be premalUre A similar atmospheric mechanism supports the to hail this phenomenon as the success of a familiar south·to-north transfer of rus[ spores in climatic fluctuation in killing off a troublesome North America. plant disease. Only time will tdl whether the return of a series of mild summers to Icdand Where. as in these cases. the itinerary of the may not reawaken a fungus which had managed inoculum is mainly over land. crops may be to slumber on at a sub-clinical level. progressively infected along the track of the spores. each successive outbreak along the route acting in turn as a fresh source. More controversial is the suggestion that disease may be carried by wind across the oceans in one giant step. Recently. the entry into South America of the dreaded coffee rust disease has 3.4 The Role of the Wind in the Spread been plausibly attributed to carriage from coastal West Africa by the northeast trade winds of Disease (Bourden 10 The Meteorology of Potato Blight OF WIGHT HENANSAL, BRI1TANY 10 March 1981 Fig 2. Air trajectory for the transpon of foot-and-mouth disease from Brittany to the UK on 10th March 1981 (after Donaldson rta/, 1982) A particularly relevant example (Fig. 2) Coincidentally. one of the earliest reported concerns the successful forecasting of the spread outbreaks of potato blight in England in 1845 of an outbreak of foot-and-mouth disease in occurred in the Isle of Wight. and followed the March 1981 from Brittany to Jersey and the Isle appearance of the disease along the northern of Wight. in association with a warm sector of French coast and in Jersey (see paragraph 5.6). maritime tropical air (Donaldson rt a~ 1982). 11 Potato Blight in Europe in 1845-6 ....r..: -00 12 CHAPTER 4 THE WEATHER IN THE YEARS CONCERNED 4.1 The Types ofWeamer Information and Meteorological Instrument Data (ii) Weather diaries. mostly without instrument measurements. but occasionally including Available once daily measurements of barometric For the reconstruction of wind and weather pressure. rainfall or temperature made from patterns prevailing in the eighteen-fonies, at the instruments of unknown qualiry. rype and times of the first appearance of potato disease in exposure. Wind directions were again usually. Europe. its spread and of the famine which but not always. included. Frequency and followed in Ireland. the types of data available timesof observation varied. butwere mostly may be classified as follows: either once daily or given as a single summary. or survcy. of the 24 hours. (i) Registers ofdaily metcorological observations (iii) Summary reportS of the seasons. sometimes including instrumental measurements. The with a few details of certain days. and sometimes including referenccs to the crops intervals between successive ob~rvations ranged from oncc daily to hourly throughout and natural vegetation etc. the 24 hours at major observatories. such as Greenwich and St Petersburg. and every 20 No official national weather services having minutes throughout the day and night at been formed as early as that time. the official Helsingfors ( now known by its Finnish weather observations were mostly made at name-Helsinki). observatories which were primarily concerned with astronomy or earth magnetism. Other The observations usually included pressure. observation registers and diaries were kept by temperature and measurements of rainfall. interested individuals-such as clergymen. wind direction and cloud cover; at a smaller doctors. farmers, landowners and scientists number of places humidiry measurements. whose standards of performance. nonetheless. often readings of the wet and dry bulb often matched those of the personnel of official thermometers, were included. The sources observatories. Their importance can be secn of observation data used in this study are from the following extracts. listed in the Appendix to this report. 13 Potato Blight in Europe in 1845-6 4.2 Notes on the Occurrences of Potato Whitehaven (Cumbdand) and in a long anide Disease included with the Weather by J Couch. ES. in the Annual Report. for that same year. of the Royol Cornwall Polytechnic Data Society (p.9 ff.). "Cultivation of the potatoc" The farm weather diary notes written at K1epp and the export of large quantities to London in Jaeren in southwest Norway include the and other cities had lately become important to following: the economy of the county of Cornwall and the "The summer of 1845 was a good normal loss of the crop in 1845 was "regarded ... as a year. with enough rain to give a tolerably public misfortune". In the eastern part of the good harvest of corn and hay. though the county the first signs of injury 10 the crop wet< dry rot increased strongly on the potatoes noticed as early as the first week of July among so that there were few of them on sale in the early potatoes. which had become watery. the village and they became dear.... " The later m,uuring varieties showed it about a fortnight later. In the previous seasons on "The summer of 1847 was extraordinary average each square yard of ground yielded "a good and fruitfUl. With the variations bushel of sixteen gallons". but in 1845 in some between rain and warmth there were a fields the crop was not worth digging. massive hay harvest. the most that anyone can t 14 The Weather in the Years Concerned 4.3 Homogenization of the is unlike the situation that obtained in the Meteorological Data previous century. when the Russian The meteorological observations and instrument obsetvations in the yearly volumes of the readings were made at various times of the day. Ephemerides of the Societas Meteorological and a variery of scales and units were used. Palatina were published under the dates of the old Julian calendar used in Imperial Russia). Where observations were made only once a day. 2 p.m. local time seems to have been by far The most commonly used temp"rarure scale the commonest choice. Nearly everywhere it in Europe generally was Reaumur (800 R = was possible to base the mapping on IOOOe). although some places used Centigrade observations made at some time between and others. including Palermo in Sicily, used midday and 3 p.m. Although synoptic weather Fahrenheit. maps were drawn up for only one time each day. notes were made of the weather reported at Pressure readings were mostly in Paris inches other times, and these were taken account of in and lines. and the pressure values usually identifYing the progress of fronts. corrected for the temp"rarure of the instrument. Some difficulry. requiring caution on the usually to OOR (= O°C). but at the Russian parr of the meteorologist. is presented by the stations to 13'12°R or 16.9°C. Adjustment of way in which time was reckoned at the these Russian barometer readings to the astronomical observarories where some: of the equivalent height of the mercury column at oDe finc:st series of meteorological instrument means adding 2.8 to 3.0 hectoPascals (millibars) observations were made in those days. to the pressure. One Paris inch was 27.07mm; According [0 either "Greenwich Mean 28 Paris inches of mercury. or 336 lines. at oDe. Astronomical Time" or the "Gottingen represented a pressure of 1010.5 hectoPascals. Astronomical Reckoning" (an analogous system However. Austrian inches (I A.inch = 26.34 determining the time for the longitude of mm). English inches (I inch = 25.40 mm). Gottingen). the day began at midday: this Rhineland inches (I R.inch = 26.15 mm). means that. for example. what we now call the Spanish inches (I Sp.inch = 23.2 mm) and 14h. observations were printed as "2h:. and the Swedish decimal inches (I Sw.D.inch = 29.7 2 a.m. observations of the following day were mm) were also encountered (JU Lamb and printed as "14h: on the day that began at Johnson, 1966. for further similar details). midday. Thus. both the times and the dates Such experiences are quite persuasive as need adjustment the 8 or 10 a.m. observations regards the advantages of the universal units were printed as "20h: or "22h: of the previous of the metric system! day. (We are indebted to the Royal Greenwich Observatory at Herstmonceux for this Some uncertainry arises about the equivalence information. which confirmed the solution ro a in modern units of some of the forms of difficult puzzle: personal communication. 18 measurement of humidiry and wind (e.g. by July 1983). pressure-plate anemometer). But some wet and The tabulated meteorological observations for dry bulb thermometers were in use. and relative the Russian stations. as printed in the sources humidiry. dew point erc .• can be calculated in here used (see App"ndix to this report). and also the usual way: some observation registers indeed for Finland which was then under Russian rule. already give the calculated relative humidity and are already adjusted to the Gregorian calendar dew point. Dew point values were plotted on used internationally elsewhere in Europe. (This the maps wherever possible. 15 Potato Blight in Europe in 1845-6 The Beaufort scale of wind force was already in 4.4 The Synoptic Weather Maps use at some places. and in some tabulations of Once daily weather maps were plotted and the observations conversion to wind speeds in analyzed. Sample days-23 July and 17 kmlhr had already been done. Other observing September 1845. as well as 31 July 1846-are stations were still using the five-point scale of illustrated in this report (Figs. 8. 9 and 10). wind force enjoined by the old Societas The analysis represents as nearly as possible the Meteorological Palatina in the previous connuy. meteorological situation at about 14h. GMT on On this scale: the days in question. o = quite light wind Plotting Conventions used I = moderate air motion bringing the leaves of The data shown on the maps here illustrated are the trees into movement limited to--Cloud Cover:(shown by blacking 2 = stronger air motion. causing the twigs and in the circles the number of quarters of the sky small branches of the trees to move covered); Present Weather:(using the modern 3 = very strong wind. big branches moving. international symbols: dust swirls up from the ground ram • drizzle , sleet .;. snow. 4 = storm. rain shower.g snow shower ~ hail shower ~ thunder K lightning seen However. by the 1840s. Norwegian stations. < fog =fog with sky visibk == mISt =haze 00 and perhaps most others also. seem to have used continuous rain; light.. moderate:. the same scale with the numbering changed to heavy ••• and so on); Air temperature: (0C); I to 5. The instruction in Norway about force Barom;tric Pressure: hectoPascals (hPa). 5 read ·only used when the wind is of storm omitting the hundreds and thousands digits); force such as here sometimes occurs with S or Wind Direction and Beaufort Force (by the SW storms accompanied by frequent hurricane direction of the arrow tails and the number of like gusts". A conversion to Beaufort force was flecks on the tail: one for each two points of the used for plotting the maps here presented. on Beaufort scale). which each full fleck on the tail of a wind arrow represents two points of the Beaufort scale. The present weather symbols are shown to the left of the circle which marks the station's In this project. regular use was made of the position. except in a few cases where a posidon gazeteer of old observing stations. with notes on at the lower right·hand side of the circle means the sites. the observers, the instruments, times rain, snow, shower (or whatever) observed of observation. scales used etc.. compiled over within the past hour but not at the time of recent years in the Climatic Research Unit at reporting. The figures to the upper left of the the University of East Anglia. Norwich. in the station circles are the temperature and those to course of production of eighteenth and early the upper right are the barometric pressure after nineteenth century daily synoptic weather maps correction to sea level and standard gravity. On for other projects. And. of course. the the original weather maps. not here reproduced information supplied with (or otherwise in full. additional items entered included: types discovered about) the 1840s data here used has of cloud (where reported). past weather (in been added to the gauteer. For the present many cases from the beginning of the day - i.e. study. observation reports were collected from previous midnight) and later weather (in many 71 places scattered over Europe from Iceland cases up to midnight). dew point temperature and north Norway to the Mediterranean and (wherever humidity measurements were from Ireland to the Caucasus. also the logs of reported) and (in some cases) extreme values of twelve ships at sea. (For further details. please temperature or pressure observed earlier or later refer to the Appendix of this report). during the day (with time of observation). 16 The Weather in the Years Concerned Types of Meteorological M.p Produced On the barometric pressure maps the isob.rs The lUll range of meteorological maps used in are drawn at intervals of 5 hPa (lUll lines) with this study inel uded: intermediate values indicated by dolted lines at intervals of 2.5 hPa. On the originals of these (i) Barometric pressure at mean ~ level (in maps wind roses. indicating the percentage hectoPascals (hPa» averaged for e.ch frequency of surface winds from different month June. July. August and September directions within the month named. were in 1845 and 1846. also entered but are not reproduced in this report. (ii) The .nomaly. or dep.rture. of the monthly mean barometric pressure in On the .nomaly maps the dep.rtures of each of the eight months named from barometric pressure and temperature from the the 1851 to 1950 average. long-period average are shown by isopleths .t 1hP. and 1°C intervals. (iii) The variability of the barometric pressure from day to day. measured by the standard deviation of the once-daily pressure values within each of the 4.5 The Meteorological Analysis: months named. Problems and Procedures Used (iv) The anomaly. or departure. of the One has to start from the assumption that the monthly mean temperarure in each of observations and measuremeon reported in me the eight months named from the 1851 manifestly carefully kept weather registers. to 1950 average temperature for the particularly at the moS( highly respected same month. observatories of that time. were reliable. This assumption can. however. be (and was) (v) The anomaly. or departure. of the subjected to a certain amount of testing at later seasonal mean temperature for the 3- stages in the analysis. month seasons June to AuguS( or A problem that also had to be resolved is the December to February from the 1851 to fact th.t few details were known about the local 1950 average temperarure for the same sites. and particularly the height above sea level season in each summer and ~ach winter of the barometers. at a good m.ny places. between 1844 and 1847. including a few of the high qualiry observation (vi) The difference of monthly mean stations. barometric pressure between 1845 and The first step. therefore. was to draw monthly 1846 (1846 values minus 1845 values) mean maps of barometric pressure reduced to for each of the eight months named. sea level. based just on the best observation records and places about which our knowledge (vii) The difference of monthly mean of the specific details mentioned above was temperature between 1845 and 1846 sufficient. This provided eight separate (1846 values minus 1845 values) for monthly mean maps. for June to September in each of the eight months named. the two years 1845 and 1846. And from these. the corrections needed to make the monthly Arrangements can be made to see the original mean pressures at all the other stations maps. or copies of them. at the Climatic reporting barometric pressure were studied. In Research Unit. University of East Anglia. nearly all cases. this yielded indications of a Norwich. Samples of moS( of these sufficiently consistent adjustment that could be categories of map are reproduced in this report. applied to the reported barometer heights at 17 Potato Blight in Europe in 1845-6 each station to make the readings useful for the drawn, and isobars sketched in, on once daily firsr arremprs at daily synoptic meteorological maps for altogether 24 days in those two years. map analysis. Many of the observing stations used in this study were ploces where weather observation The dates for which maps were completed and instrument measuremenrs had already been 1845 1846 made many years earlier, in the previous 14 - 16 June century, and used in the daily synoptic weather 3 - 9 July 28 - 31 July maps (mainly covering the years 1781 to 1786 20 - 24 July 7 - 8 August and some months in the 1790's) reconstructed 16 - 18 September in the Climatic Research Unit. This meant thar some details of the sites etc. could be learned from the Gazeteer of early Meteorological The dates were chosen in connection with the Observing Stations, compiled in the Unir. In a history of the developing outbreaks of the few cases, however, as was natural, it became potato disease. This analysis revealed that there obvious that the instruments had deteriorated were some places where the pressure values with age by the 1840's. derived from the instrument readings gave more Maps of the day-to-day variability, in terms of trouble than others. The average, and the standard deviarion, of pressure over the entire extreme range, of the discrepancies at each place area studied from Iceland across Europe were between the pressure value entered on the map drawn for the basic purposes of discovering: and the best·fit isobar analysis of the whole map were logged. On this basis, a modified value of (i) the belts, or zones, of most activity of the standard pressure adjustment' to be adopted cyclonic disrurbances, which in general for each place was decided: and a note of this cause the greateS( variability of pressure and the magnitude of the error range was level within each month; added to the details for each station in the Gazeteer. (ii) any individual stations where a high variability figure untypical of the The standard errors of the pressure values so surrounding area on the map indicated adjusted were one hPa or less at the best stations that the barometcr, or the observer, must (e.g. 0.5 to 0.7 hPa at Brussels, Copenhagen, be regarded as unreliable. An unrypically Den Helder (Holland), Geneva, Helsinki) and low variabiliry figure should also attract only 1.7 to 2.3 hPa in the case of the Danish interest, since it could for example indicate naval ships in port or at sea in the southern extreme trouble with sticking of the North Sea, Baltic and English ChanneL The barometer (sticking needle or mercury higher figure of 3.0 hPa for ships operating in column). the Faeroe Islands - Iceland region may be partly attributed to the difficulties of precise At this stage, the firsr analysis of the synoptic analysis with strong pressure gradients and meteorological maps for the individual days more rapid changes of pressure in that region. selected for study in 1845 and 1846 could be Notably, higher values of the s(;\ndard error at carried out. An airmass and frontal analysis was two points indicated that the barometer ll\.fctcorologica1 readers wlll be aware due the: correction of barometric pressure: (0 sea level etc should vary a linlc from d.;ay to day, depending on the air temperature and pressure: level. However this refinement lu.d to be 1argdy disregarded beau><: of time restriction in the present study. 18 The Weather in the Years Concerned readings on certain particular days. at Ballimore very many places produced humidity records in the western Highlands of Scotland could be that were obviously self-consistent and fully treated as quite untrustworthy and that the old credible. "may be that the requirements for barometer at Montdidier in northern France proper exposure and maintenance of the wet (which had performed well in the 1790·s). had bulb thermometer were not widely understood to be disregarded in the years 1845 and 1846 at that time. Luckily. the humidity here studied. measurements at both Dublin and Brussels. The corrected pressure values at stations with which this srudy is necessarily concerned. where there was least specific knowledge about do appear reliable. as do those at a number of site and instrumenu have been entered in other high-grade stations. brackets on the daily maps. even in those cases where the results from the corrections derived give apparently consistent and reliable pressure values that fully support the analysis. Pressure values derived from the barometric 4.6 Results of the Meteorological measurements in ships have also been entered Analysis: The Nature and in brackets on the maps in this study. Development of the Seasons The derivation of maps of monthly mean 4.6.1 General temperarure for the eight months studied was The eighteen-forties were a decade of special not a simple matter. because many of the interest climatically being one of the final stages observers only read their instrumenrs at one, of the long period of colder climate in recent twO or three times of the day. and these times centuries that has beeome widely known as the differed from place to place. This. however. Little Ice Age. In the 325-years-Iong meant only that detailed large-scale mapping of thermomC'tI:r record of temperatures in central the tern ~rature variations within an area such England (Manley. 1974; Lamb. 1977) it as the British Isles. where there were twenty displays one of the three longest runs of cold three stations reporting. could not be done summersi eleven out of twelve summers without the expenditure of a great deal of time between 1838 and 1849 have a mean in study of the diurnal temperature curves. temperarure Uune. July and August) of 15.0OC There were enough places distributed over or less as against an average of 15.6°C in the Europe. however. for which daily maximum and present cenrury. Only the 1690·s. with a ten minimum temperatures were recorded (i.e. the year mean of 14.5°C and 1809-18 with 14.6°C highest and lowest temperatures in the 24 hours appeared colder. On the other hand. one recorded by automatic instruments) to make it summer (1846) in the 1840's was out of line possible to map the general pattern of with this in England. with a mean temperature temperature deviations over the region as a of 17.1°C. one of the warmest on record. whole for each month and each season. compared with 17.6°C in 1826 and 1976. The possibilities of a really extensive survey of The glaciers in the Alps were still near their the occurrence of potato blight weather most advanced positions down in the valleys. conditions in the eighteen-forties were limited the extremes being generally reached in dilTerent by shortage of reliable humidity measurements. cases around either 1850 or 1820 (as well as Although wet and dry bulb thermometers were earlier around 1600 and 1720). in evident already in use at a good many places. and other response to periods of cold summers. But the types of hygrometer were also employed. not great recession. which continued with little 19 Potato Blight in Europe in 1845-6 interruption until 1965 or after. was about to 4.6.2 The Wmds and Temperatures in 1845 begin. And symptoms of a warmer climate and 1846. beginning were already apparent in another part The years with which we are concerned here of the European environment. with the had rather more days with southwesterly wind disappearance for fifteen years of the Arctic sea in London than the average of the eighteen ice from Iceland waters: it was not seen at the fonies decade. Nevertheless. the temperature coasts ofIceland from 1840 until 1855. and pressure maps over Europe and the eastern Features which doubtless correspond to these Atlantic for June to September 1845 and 1846 changes affected the prevailing wind climate. all show features characteristic either of The long record (Lamb and Weiss. 1979) of the blocking of the westerlies in some part of the frequency of days with general wesrerly winds map or of a lower than normal latitude of the blowing over the Btitish Isles runs from 1781 to main westerly wind flow over the whole region. 1786 and from 1861 to now. It is the The maps of temperoture departure in each commonest single type of situation and is month from the long·term (1851-1950) average regarded as a basic feature of the European reproduced here in Figs. 3 and 4 all show some climate. region of temperature anomaly over western or Although it does not Cover the eighteen central Europe with decidedly different forties. the correlation with the frequency of experiences indicated in other longitudes. cast southwesterly surface winds in London. which and west of iL This is an indication of regions is known-it is a record of observations unusually affected by northerly or southerly unbroken from 1669 to the present-indicates winds or. in some cases. of repeated influence of an average for 1840-49 of about 70 general either cyclonic disturbances with cloudy skies wesrerly days a year. This is a higher figure and rainfall or of anticyclones with fine weather. than those indicated for the severer phases of In the seasonal temperature departures (Fig. 5) the cold Little Ice Age climate before 1830. and this is less obvious because of shifts of the is, in fact, quite similar to recent years (since persistent warm or cold. wet or dry influences 1968). although in the 1860·s. and between from one month to the next. Samples of the 1900 and 1954. the average was between 90 barometric pressure maps. for July 1845 and and 110 days a year. So. in this sense the July 1846. are reproduced as Figs. 6 and 7. eighteen-fonies appear more particularly similar Table 4.1 shows the percentage frequencies of to the present day. The figures regisrer how winds from directions of interest to this study at wide the long-term variations are in the Dublin in the months from June to September frequency of so-called "blocking of westerlies. 1845 and 1846 (Ordnance Survey of Ireland. when wind and weather parterns differ more or 1856). When converted to percentages of the less subsrantially from the supposedly normal average for the years 1831 to 1852. the mosr prevailing westerly winds situation. remarkable features in 1845 were the high Table 4.1: Wmd Dirrcction Frequencies in Phoenix Park. Dublin for months June to September (Percentages of the observations) 1845 1846 Jun Jul Aug Sep Jun Jul Aug Sep SW+W 42 32 34 42 32 56 28 32 NW 20 15 29 6 1 8 1\ 8 NE+ E+ SE 12 27 6 27 45 12 36 45 Calm 17 16 16 17 3 1 8 6 20 The Weather in the Years Concerned Fig. 3 Anomalies of the air temperatures prevailing in (a) June. (b) July. (c) August. and (d) &ptember.1845 -i.e. departures in °C of the monthly mean temperature from the 1851·1950 average. frequency of calms in each month. the from easterly points. particularly from the SE. frequency of winds from easterly points in July. was quite unusual. In July. however. winds from and the frequency of NW winds in June and between Sand W accounted for nearly three August. All were about twice as prominent as quarters of all the observations. a frequency usual. In 1846 the winds were not so light; nearly twice as high as their usual. and. except in July. the prominence of winds 21 POlato Blight in Europe in 1845-6 Fig. 4 Anomalies of the air rcmperatures provailing in (.) June. (b) July. (c) August. and (d) September. 1846 -i.e. departures in °C of the monthly mean temper.ture from the 1851-1950.verage. 4.6.3 The Winter righ' .cross the continem. Additionally. in Four of ,he wimers of the decade (1839-40. 1841-2. and 1847-8 •• simil.r windstream. 1842-3. 1845-6 and 1848-9) were marked by passing over or ncar western parts of the very strong wind circulation sweeping mild British Isles. drove mild .ir from the SW .nd S Atlantic air in cowards Europe Olnd at times far in to the Arctic. The other winters of the 22 The Weather in the Years Concerned Fig. 5 Anomalies of the Mean Air Temperatures for the (a) summer of 1845. (b)winter of 1845-46. (c) summer of 1846 and (d) winter of 1846-47. i.e. summer departures in °C of the Mean Temperature of the period June. July and August and winter departures of the period December January and February from the 1851-1950 average. decade showed more distorted patterns. The February between 1.0 and 2.5OC below the 1851- winters of 1844-5 and 1846-7 (Fig. 5(d» 1950 average over most of the British Isles and were cold. with the mean temperature of the about 4°C below average in parts of continental three months December. January and Europe and Scandinavia. By contrast. the winter 23 PoUto Blight in Europe in 1845-6 Fig. 6 Mean baromemc pn:ssun: at sea level in bectoPa.scaIs in July 1845 Fig. 7 Mean barometric press un: at sea level in bectoPascals in July 1846 1845-6 (Fig. 5(b» was very mild. with mean record. whereas the figure for 1846-7 was - temperature up to 3°e above normal in O.6°C. Sabine (J 846) writing about it at the central Europe. time. along with two earlier winters noted for At De Bilt in the Netherlands the mean their exceptional mildness (Jn6-7 and 1821- temperature of the winter three months 2). was able to report that the warm water of (December to February) in 1845-6 was as high Gulf Stream origin advanced far beyond its as +5.re. one of the highest in a 300-year usual bounds in the eastern Atlantic. 24 The Weather in the Years Concerned 4.6.4 Sea Surface Temperatures and 4.6.5 The Summer ofl845 Atmospheric Humidity The weather in all three of the main summer We do not have the sea surface temperature months of 1845 was dominated by cyclonic observations made in individual years in the disturbances over the Atlantic passing from eighteen-forties at hand. It is likely. however. southwest [0 northeast, or from wC'st to east. that the warmer than usual water remained a near the British Isles. The axis of lowest feature of the ocean surface near the British Isles pressure. in each =. passed between Scotland into the summer of 1846. This conjecture and Iceland. where nonherly winds prevailed. could not be justified on the basis of persistence At times. the high pressure whose prevalence is alone; but the winds observed in Ireland. implied over the Greenland region extended or showing excesses of southwesterly and southerly was temporarily displaced far south towards directions in nearly evety month to July 1846 Scotland and England. the southern NOM Sea. inclusive. make it probable that the drag on the or south Norway. At such times. weaker ocean surface continued to drive the warm cyclonic depressions with th undery activity water towards these islands. And so. higher moved eastwards over Europe. mainly between than usual atmospheric humidity could be France. southern Germany and Poland. or maintained. Monthly averages of the dew point Austria. while others approached Ireland from temperature at Dublin show the effect (Table the southwest. During late July. August and 4.2). Dew points were higher in 1846 than in panicularly in September 1845. northwesterly 1845 in all the months studied. The average and northerly winds were established over the difference was more than rc. And this was Notwegian Sea. reaching at times as far south as not in the main due to the greater frequency of Orkney and Shetland and on over eastern northwesterly and northerly winds in 1845. England and the North Sea. bringing high The difference b"tween the two years was frequencies of N winds to Holland and NW almost as great when the: comparison was winds to Denmark. This supply of cold air is a confined to days with similar winds. from the prominent feature of the temperature maps southwest quaner and from the Irish Sea coast (Figs. 3(b).3(c) and 3(d». particularly in nearby. September 1845 (Fig. 3(d». And. as will be TABLE 4.2: Dew Point Temperature (monthly averages) from measurement at Phoenix Park. Dublin 1845 1846 June July Aug Sept June July Aug Sept Dew Point ("0 at 15h 12.3 11.7 11.8 9.6 14.3 13.4 14.3 13.2 Difference 1846 minus 1845 2.0 1.7 2.5 3.6 Dew Point ("0 on days with winds from ~een WSW through StoNE 13.1 12.3 13.5 10.8 14.6 14.5 14.6 14.1 Difference 1846 minus 1845 1.5 2.2 1.1 3.3 25 PO"ltO Blight in Europ<: in 1845-6 noted in Chapter 5. it doubtless explains the Europe than in 1845. by more than 5 failure of the potato disease to reach the hectoPasca.ls in a belt from northern Scotland to northernmost parts of the British Isles in 1845. Scandinavia. in June. August and September. And. even in July 1846 the high pressure over central Europ<: extended a ridge over the North Sea to southern Norway. Thus. continental Europe and eastern England were protected 4.6.6 The Summer of 1846 from Atlantic depressions. which again affected In 1846 the SC TABLE 4.3: Number of Days with measureable Rain and the Total Rainfall each Month 1845 1846 June July Aug Sept June July Aug Sept London (Chiswick Royal Horticultural Society) DaY' with rain 12 21 17 14 6 14 16 9 RWUaIJ{mm} 34.5 58.7 70.9 45.0 20.3 45.3 114.3 44.7 Dublin (Phoenix Park) DaY' with rain 16 19 21 18 10 20 24 20 RWUaIJ {mm} 83.8 70.6 62.2 26.4 24.6 74.4 121.7 54.9 26 The Weather in the Years Concerned 4.6.7 Day-by-Day Weather and the Potato Fig. 9 illustrates a much more cyclonic Disease sequence, with active fronts across most of There is no doubt that there were enough Europe. in the early autumn of the sarne year. occurrences of easterly wind in the summer and The depression centres were mainly between early autumn of 1845 to carry the potato blight latitude 50 and 60oN. and one of them infection in Belgium to Ireland. And there deepened to about 970 hPa as it approached were plenty of occasions with winds from other the Faeroe Islands on the 18 September 1845. directions. able to account for the spread of the The map for September 17th. illustrated in the disease to the other parts of Europe. from south figure. shows strong Sand SW winds Norway to southern France and east as far a developing near the British and Dutch coasts Germany at least. The three daily weather and a very wide area of rainfall. Temperatures maps in this report have been chosen to and dew points in all the warmer air masses illustrate sequences which clarify the spread and over Ireland. Britain and the continent after the distribution of the disease (Figs. 8-10). leading warm front were high enough to sustain potato blight development. In Germany. air Fig. 8 shows the weather situation on the temperatures exceeded 25°C in this air on the afternoon of 23 July 1845. The days from 20 18th. but in most places the continuing cloudy to 24 July were analysed. Pressure was high to overcast skies. associated with all the frontal over the Norwegian Sea throughout that time. activity. kept the temperatures a few degrees and an anticyclone eentre moved south to lower and relative humidity high enough to become established between Scotland and the foster the blight. Faeroe Islands. There were weak low pressure The weather map for 31 July 1846 (Fig. 10) systems stagnating. or moving slowly eastwards has been chosen to show one of the many over the continent from Biscay. over Briranny weather situations of that year which. although and south Germany. to Austria. And there was partIy similar to the maps of 1845. gave much a good deal of thundety activity. showers and finer. warmer weather over much of Europe. occasionally heavy rain. followed by fogs at especially northern Europe. Cyclonic activity night. along and near the fronts dividing the again maintained frequently overcast skies and warmer air over central and southern Europe humid conditions over Ireland and. sometimes. from the colder air that came south over other parts of the Atlantic fringe; but elsewhere Scandinavia and the North Sea. there was much less cloud and some vety high At first. on the 20th. there were easterly temperatures. The map shows 30°C in winds all the way from north Russia to Ireland. Stockholm and Copenhagen. 31°C in London But on the 22nd·23rd the warm weather that and 32"(; or over at several points in northern had extended as far north as Stockholm and France and western Germany. Christiania (Oslo). with temperatures 26 to A week later. on 7-8 August 1846. weak 29"(; on 20th-22nd July. was replaced by much cyclonic centres had penetrated east as far as colder air from the north. On the 23rd-24th Denmark. bringing thunderstorms into the main channel of the cold air supply was southern Scandinavia and widely OVer central transferred west to the North Sea. and Europe. where temperatures still ranged from afternoon temperatures were as low as 15 to 26 to 33"(;. With the overcast skies in the next 16°C in southern England. At this point the few days after that activity. there must have winds were more northeasterly in England and been an interval when the thr 27 Potato Blight in Europe in 1845-6 ",. ~. ~1 ,., • I i' I I tiJ • ( / , / \. / f • • • Hl45 JULY 23 • Fig. 8 Synoptic Weather ~bp: situation at 14b on 23 July 1845 28 The Weather in the Years Concerned ,./ ,/ '" • .... ---... e' b . ----- ...... - --...... - • --...... • -" \? \ • LOW • ... , • 1845 SEPT17 Fig. 9 Synoptic Weather Map: situation at 14h on 17 &ptember 1845 29 Potato Blight in Europe in 1845-6 ,.... - o • -#> -0=-< 'L...-.?~=;C:.~, .." ( ~\ ...~ LOW ~ • -~-c'" ./::..~ -(;.:/ 1Od. ---/--"-/ 1 1846 JULY 31 Is Fig. 10 Synoptic Weather Map: situation at 14b on 31 July 1846 30 CHAPTER 5 POTATO BLIGHT IN EUROPE IN 1845 5.1 Data on the Blight Epidemic Courtrai (Kortrijk) in West Flanders towards It is possible to chart the onset and the end of June (Bourke. 1964). The dates of development of the 1845 outbreak of potato the first recorded appearance of disease in each blight in Europe in fae greater detail than that district were plotted on a large scale map. and of any subsequent anack down to the present iselines for fortnightly intervals were drawn to day. This is because the spectacular first impact envelop all attacks which were described as of the disease and the level of public concern serious by the date in question. led to the appointment in most of the affected In areas of particularly abundant reports such countrics of governmental commissions which as Ireland. where the numerous police returns compiled comprehensive reports on the were supplemented by much extra material. epidemic. Similar accounts were prepared by some outliers oftesser impact were found to be the special commin«s set up by many scientific located beyond the lines of main advance. as and agricultural bodies. Detailed weekly was no doubt to be expected because of the reports on the impact of the disease in Ireland windbome spread of the disease. in 1845 and 1846. drawn up by the constabulary at more than 250 police Slations It is important to note that the dates shown throughout the country. are preserved in the in Fig. 11 are those on which the disease Public Record Office. Dublin. A flood of attracted general attention and published books. pamphlets and newspaper articles was comment. not those on which the fungus first devoted to the subject. The accounts published began its attack. In the early inner zones. they in the Gardeners' Chronicle (hereafter referred are thus the dates on which foliar decay was to as GCl. covering moS! of Europe. are sufficiently advanced to amact the concerned particularly voluminous and helpful. Useful attention of persons hithetto unfamiliar with data are to be fou nd in publications as dive~ the distase; in the outer zones. where natural as the Moniteur Beige (MB) and the Irish ripening at so late a date in the growing =n Farmers' Journal (IFJ). tended to mask the progress of the disease on the foliage. the first alarm often dated from the discovery of tuber rot. For example. when the 5.2 Synthesis of the Disease Data constabulary in Ireland were first asked to Fig. 11 is a pioneer reconstruction of the spread report on the disease in mid·September 1845. it of the epidemic based on the approximate dates was for tuber rot that they primarily looked; when blight came to attention in 1845. many of their reports made only incidental commencing with (he earliest report from near mention of premature decay of the foliage. 31 Potato Blight in Europe in 1845-6 w"" ..so w ..> ~ <> E Fig. 11 Dates in 1845 when progccSS of blight was so generally noticeable as to cause comment and alarm 5.3 Checking the Disease Picture I last wrote to you I am sorty to say that the The essential accuracy of the broad lines of Fig. potato.murrain has made its appearancc in 11 has been confirmed by different types of Northamptonshire and is spreading vety rapidly" supplementary information. Thus, for cxample, (GC 1845, p.608). at a mccting of the Societe Royalc ct Contrale An unexpected by.product from some of the d'Agriculture held in Paris on 20 August 1845, weather diaries kept by farmers in the year 1845 (Bulletin de Seances, 1845·6, p.284), M. Elisee proved to bc comments on the blight cpidemic Lefebvre put on exhibition samples of diseased which tended to confirm Fig. 11. From potato foliagc and tubers which he had ~tontdidjer, ncar Arnie-ns in northern France, collected in [he Brunoy suburb of Paris. On 30 the 'maladic:-de moisissurc' was reported as August, Dr M J Berkeley in England received auacking thc potato crop in August, affecting from his friend and fellow mycologist, Dr J F first thc foliage and thcn thc tubcrs. In Montagne of Paris, 'some leaves affected with Uckfidd, south of London, the diarist felt that [he mildew'. Dr Berkeley made enquiries in 1845 would bc particularly rcmembcrcd for the cvety direction but failed to locate the disease in appearance of potato blight as a new disease. the neighbourhood of his parsonage at King's He first noticed it on 28 July; within [tn days it Cliffe, near Peterborough. His own potato crop had bccome rife throughout Sussex, but it was was 'ncver more abundant or finer' (GC 1845, absent from the north of England until early p.593). No more than a week later the position September. The observer at Ipswich recorded had changed dramatically for the worsc: "Since damage to the potato foliage as beginning in 32 Potato Blight in Eurol'" in 1845 early August; by the end of that month ",he Wolverhampton and Crewe some had escaptd whole crop appears as if completely seared". lightly. Between Hartford and Warrington, and From Tutbury in the English north Midlands close to Liverpool, things were much better. He notes on the month of September say that the hoped that the progtessive improvement which disease was in large measure confined to the he found in travelling from the SE towards the more southerly counties; locally it had been NW of England might prove a hopeful sign for only partially felt. The diarist casts doubt on the Irish potato crop. the theory that the damage to ,he crop was the He was, of course, unaware that three direct result of unseasonable weather: "we have considerable periods of blight weather, with a had similarly wet seasons without any similar combined effective duration of 67 hours, had result" . occurred during his absence from home (see Some accounts of cross-country journeys Fig. 13). Returning to Mallow on 20 provide cross-sections to verify Fig. 11. Mr J September he was shocked to find that every Dillon Croker set out early in September from one of his potato fields had changed from rich his home near Mallow, Co. Cork, for a journey green to the dark brown and black colour which to London. He wrote lengthy letters on the indicates the ravages of blight. Only in a small condition of the potato crops en route to the part of one field had tuber rot as yet set in, but Cork Constitution which were widely copied in there were many complaints of this among his other newspapers. When Mr Croker left home neighbours. on 8 September his potato fields were generally Most of the newspapers in Ireland which luxuriant, except for two partially withered reprinted Croker', letters, esl"'cially those in the which at the time he attributed, more midlands and west, felt that he was unduly significantly than he knew, to the east wind. pessimistic about the crop. There was no Travelling on 10 September between Bristol and general panic in Ireland for another month or London, he did not see a single exception to a so, until the extent of tuber rot was revealed at total failure of the potato crop, the stalks all digging time. decaytd and dying. Many of the fields looked like an undug garden in January. His son, a student at Cambridge University, told him that the epidemic had swept to the north of that town. He understood that blight also raged in 5.4 Windbome Spread from an Infected Holland, Belgium, Germany and France. Central Area? The pattern of successive discovery of blight in In the following week, Croker travelled 1845 as depicted in Fig. 11 is consistent with a northwest from London to Liverpool, where he gradual outward windborne spread from an noted that one-quarter of the potato crop being initial infection area centred on Belgium. At brought to the market there was found to be first sight such an interpretation may ,eem unfit for sale at the first picking, while a further improbable in view of the high vulnerability of proportion rotted later. On the journey from blight spores to all but humid weather, which London to Birmingham he saw only few means that they are normally shorr lived. surviving porato fields; in many cases a However, the geographical analysis of the spread replacement crop had been sown to follow the of blight in North America in 1843-5 (Fig. 1) destroyed potatoes. shows annual extensions of the disease over From Birmingham to 'X'olverharnpton all the comparable distances. A more recent fields were in poor shape, but between experience confirms the 'alarming rapidity' with 33 PotalO Blight in Europe in 1845-6 which a rather similar disease, the blue mould further development of the dry rot which had of tobacco, could move from local points of been particularly troublesome in «c 34 Potato Blight in Europe in 1845 extension of the disease on either shore of the riddled with blight. It might have been English Channel. In England damage by blight thought that the Belgian potato crops. already was noted in the first days of August near destroyed by the disease in earlier months. Sandwich. Kent and was quickly found in other could suffer no further damage from this later coastal areas towards the west. South of the spell of blight weather. However. a number of Channd the potato crops were soon ravaged all Bdgian growers had re-seeded their potato along the Cotes-du-Nord. the damage being fidds after the July failure. only to see their dated back by some observers to the first days replacement potato crops go down after the of August. The blackened belt of destruction mid-September a((ack (Dumortier. 1845. along the coast was ascribed by some to the p.285). passage of a ball of fire (MB. 31 August 1845). From Normandy or Brittany the disease soon appeared in Jersey. where the observer· at once attributed it to the easterly winds" (GC 1845. 5.7 The Northern Boundary to the Spread of p.576). words which would later be echoed by Blight Croker in Ireland. Almost simultaneously with In the unusually cold growing season of 1845 its appearance in Jersey. blight was found in the (Fig. 3) it was inevitable that the disease. at Isle of Wight (cf. paragraph 3.4 and Fig. 2). some stage of its march towards the north. should encounter the kind of discouraging A pressure pa((ern which recurred during temperature conditions which have inhibited many of the continental blight periods in June its impact in Icdand in recent years (see and July of 1845 fearured high pressure to the paragraph 3.3). The temperature anomalies for north of Scotland with a weak ridge extending September 1845 (Fig. 3(d» are particularly southwards and a complex set of shallow. significant; at this stage when the epidemic was thundery depressions over the Low Countries pressing northwards in Britain. the and France. A characteristic example is comparatively delayed appearance in Yorkshire provided by the synoptic chart of23 July 1845 (Fig. 11) reflects the colder conditions in (Fig. 8). This siruation gave rise to a light. but northeast England. Temperatures were still persistent. easterly wind-drift down the English lower in the north of Scotland. Milne (1847) Channel while simultaneously creating blight lists the average temperature in September weather (see paragraph 3.2.2). This is reflected 1845 for a large number of Scottish locations: in Fig. 13 where a succession of blight weather in northern Scotland the levd was sufficiently spells are recorded at Brussels in the second half low (10°-11°C) to explain the failure of the of July 1845. with no corresponding spells in disease to secure a foothold there in 1845. The Dublin. temperature check to the spread of the disease The other main blight· fomenting pressure was fated to be short-lived; in the warmer panern. as described in paragraph 3.2.1. is summer of 1846 (Fig. 4) blight would extend illustrated in Fig. 9. in which broad. warm to the whole of Scotland and to the islands sectors of maritime tropical air are shown beyond. driving eastwards into Europe. giving widespread and repetitive periods of blight The impact of blight on crops grown on high weather in Dublin in the week ending 20 ground in the cool summer of 1845 was September. and a little later in Brussels. It will similarly affected. In Irdand the growing be recalled that it was at this time that Croker population and the ever rising demand for returned to Mallow to find his potato fidds more ground to grow the essential potato had 35 Potato Blight in Europe in 1845·6 driven the crop higher and higher into the hills time lag before the more resistant varlelieS where signs of its cultivation. high above the could be multiplied and brought into general current level of tillage. persist to the present use. day. In 1845 it was found that the potato crops grown in the cooler uplands suffered 5.9 Blight Weather in 1845 appreciably less from blight (lFJ 1846 (I). p.1185; 1846 (11), p.I77). In the warmer There was much controversy in 1845 as to summer of 1846 they would no longer escope: whether the weather in that growing Season "the mountain lands which were unaffected or was. in itself. an adequate cause of the failure of but partially affected last year (1845) are the potato crop. Those who took the trouble reported to be very much affected by the to compare: the meteorological data of that year disease this year"(Thirteenth Annual Report of with the figures for earlier years agreed that the the Poor Law Commissioners. 1846. p.123). summer of 1845 had indeed been drab. cool and cloudy. but were equally unanimous that there was no feature of that season which had not been equalled or surpassed in earlier years 5.8 The Susceptibility of DilTerent Potato through which the potato crop had come Varieties to Blight unscathed. Only Harting (1846), who A great number of different poUto cultivars examined the weather records for Utrecht and were grown in Europe in 1845. many to a Breda for the years 1838-45. noted that the limited extent (Bourke. 1971). As few rdative humidity of the air had been unusually commentators failed to note. they presented a high in 1845. and related this to a finding by wide range of resistance to the new disease. Unger in 1833 that high humidity was Trials to quanti/)' these differences were carried significant for the development of many plant diseases. Ollt in several countries. For example. a replicated study of tuber resistance in rwo kinds The correctness of Harting's observation is of soil lOok place in the Netherlands on 148 confirmed by the entries for Brussels in Figs 12 different potato cultivars and gave results and 13. which portray the occurrence and ranging from complete rotting to perfect effective duration of blight weather spells. as soundness (Harting. 1846. pp.288·9). It was defined in paragraph 3.1. The first of these the increased use of the less susceptible sorts. figures relates the early season development of hitherto in limited cultivation. which enabled blight in Belgium in 1845 10 a similar first the potato to recover from the initial disaster appearance of the disease in Chile in 1950-51 and to survive as a major food crop over the (Bourke. 1956) and to a recent case of a severe lengthy interval until breeding for resistance to early attack in the Low Countries in 1981. blight and the use of fungicides had been The year 1981 was selected with the kind introduced. assistance of Professor J C Zadoks The tragedy lay in the fact that the potato (Wageningen) as one in which potato blight in varieties most widely grown by the poor the Netherlands and Belgium attracted wide because of their higher yields - such as the ill attention in the popular media by reason of its famed 'Lumpe" which was almost universally early and severe onset. It commenced as early grown in Ireland - were precisely the sorts as the first week in June. and progressed with which succumbed most rapidly and most such rapidity that it much alarmed the growers. completely to the new disease (British and revived memories of. and professional Cultivator and Agricultural Review. 1845. interest in. the 1845 precedent (Semal rt al. p.334; 1FJ 1846 II. p.222). There was a tragic 1983). The analysis of blight weather in 36 Ha, Jun. Jul, AHSTERDAH ~) ~~ , G~ ~ 1981 t t t t • .i BRUSSELS ® ~~ G~ G~ 1845 • . tt t L . 1 Novemb.r Dectllber January. SOUTHERN CHILE ( ~ (~ G) 1950 - 51 i-+--RKord. dlllC~"---.l • • • • t LONGER SPELLS IiTERHEDIATE SPElLS SHORT SPELLS LEGEND: I" 110 h...... or lIor.' t " 15-9 hours) • • IlIss than 5 hour.) Fig. 12 Blight weather spells and their e/Tective duration (in hours) in scuon. of early development of potato blight in the Netherland., Bdgium and Chile 11'1 Jun. July Augu,' S.pt.mb.r BRUSSElS ~ G~ ~o) lB~S ~~ j t i tt • •• L. l _11 t fJl_ ... • t. DUBLIN ~~ (10)1 10) 18~S .. .t If 1.. • • • tTI • DUBLIN ~ ~ e ~~o 1846 ~.) lir~ • 1 .. l • ., . .. .. it 5° BRUSSelS O(~ 1846 1 .. •• 1 f 5° DUBLIN ~ (, i> 11~7 ., .. , .. • LONGER SPEUS INTERHEDIATE SPEllS • • SHORT SPELLS LEGENO: 9 . I • 111 hours or lOor.1 t 15 -9 hoursl lless than 5 hoursl Figo 13 Blight weather spells and their effective duration (in hours) in Belgium and in Ireland during the potato growing seasons 1845-7 Pocato Blight in Europe in 1845 Amsterdam in the first three months of the escaped widespread attention by that time. 1981 growing season (Fig. 12) confirms that Later in the year a meteorological mechanism three infection cycles had already occurred by 1 affected wider areas (as in Fig. 9) which gave June. and shows that the weather in June and rise to corresponding spells of blight weather July 1981 was substantially more favourable to both in Ireland and Belgium. blight than that in Brussels in the Before considering the 1846 season in detail corresponding months of 1845; nevertheless the in the next chapter. we may draw some broad greater resistance to disease of modern potato conclusions from Fig. 13. The 1846 growing cultivars combined with the use of fungicides season in Ireland would prove climatically very sustained the 1981 crop until better weather favourable for the disease. although by no conditions prevailed in August and September. means uniquely so; the EBH toul in one Thus. although the air humidity in Brussels modern year (1958) was nearly one-third higher in 1845 was above average. it was not so much than in 1846. The figure correctly reflects the abnormally favourable weather conditions in contrast of severe disease in Belgium in 1845 Belgium which favoured the violent impact of and its slight impact in 1846. In the laner year. the disease in 1845 as the high vulnerability of the contrast between the Dublin and Brussels the crop. The same was true of the first Chilean totals of blight weather foreshadows the epidemic of 1950-51 (Fig. 12) in which the irregular distribution of blight in 1846. with. as partial deficiencies of weather records do not we shall see. the disease rem.ining relatively conceal the comparative infrequency of blight dormant in continental Europe while it raged in weather. Ireland. Fig. 13 shows the dates and effective duration of blight weather spells (EBH) (see para. 3. I) during the whole growing season for Brussels 5.10 Losses Caused by Blight in 1845 and Dublin in 1845 and 1846. as well as for Without question. the greatest damage to the Dublin in 1847. a dry sunny year of little potato crop in 1845 occurred in Belgium. blight. The totals of EBH over the potato Holland and neighbouring areas. i.e. the inner growing season are a fairly crude index of core of earliest attack in Fig. 11. Where the disease impact. especially in seasons where the haulms had been destroyed by the middle of foliage was dead well before the normal harvest July only about 30 per cent of the normal yield date; nevertheless. it is of interest to compare would have been formed at the time of death of the Dublin figures of total EBH for the years the plants (see paragraph 2.4. I). This figure 1845 (191). 1846 (303) and 1847 (67) with the must be further reduced to allow for losses due corresponding figures for a recent period of 25 to tuber blight; in Ireland these averaged 40 per years - 1957-81: minimum 28. mean 110. cent in 1845 and in places reached as much as maximum 391 (Keane. 1982). 75 per cent. The quoted figures for the 1845 Dutch harvest of 24 per cent and the Belgian of In the earlier months of the 1845 season. 12.7 per cent are therefore not unreasonable when continental-type shallow depressions (as (Bergman. I 967; Mokyr. 1980). in Fig. 8) were setting up frequent spells of blight weather in their locality. there was less In the outer zones of Fig. 11. where the blight weather in Dublin. Nevertheless. potato crop was moving towards ripeness by the sufficient favourable weather occurred before time the disease struck. losses were mainly due mid-July that. had the inoculum of blight been to tuber blight. They were heavy enough to present in Ireland. the disease could not have cause s~ere distress even in Switzerland where the effect on the lives of the very poor is vividly 39 Potato Blight in Europe in 1845-6 described in the famous novel. Klithi. die of 1845 and 1846 should be greater than in the Grossmutter. by Jeremias Gotthelf (Albert Low Countries. However. the dependance upon Bitzius) published in 1847. In Ireland. the the potato was far greater in Ireland where the average tuber rot of 40 per cent operated on a per opita annual human consumption stood at crop which had yielded remarkably well. so that 0.8 tons as against 0.3 tons in the Netherlands. the production of sound tubers was only a while the normal diet of a Dutch working man quaner or a third below normal. was not confined to potatoes as in the case of At first sight. it may seem odd that the the majority of the Irish. but included rye and resultant distress in ireland between the harvests other foods (Visscring. 1845. pp.9-12; Bourke. 19G8). 40 CHAPTER 6 POTATO BLIGHT IN EUROPE IN 1846 6.1 The Vulnerabiliryofthe Irish Potato Crop previously encountered-disaster was For Ireland. as for all countries on the outer inevitable. Only the timing and extent of that fringe of Fig. II. blight arrived late in 1845 and disaster remained to be decided. depending on struck only a glancing blow at the potato crop the weather. of that year. But the foundations were laid in these peripheral areas for a much greater disaster in 1846. should the weather prove 6.2 1846. A Year of Remarkable Weather favourable to the disease. The late autumn Despite the best efforts of those who argued attack of 1845 and the widespread abandoning that the European potato failure of 1845 was of diseased tubers in the fields at the end of the the direct result of a climatic aberration. it season guaranteed a high carry-over of proved impossible to pin the blame on the inoculum into the following season (paragraph seasonal weather. The weather of 1845 had. in 2.6). Ireland. in particular. was in a highly truth, been drab. cloudy and cold. but also vulnerable position. Its whole economy was quite undistinguished. Earlier years which had built around the potato. upon which a large been wetter and colder had seen the potato crop part of the population depended exclusively for standing up stoutly to the conditions. In 1846. food. Consequently. the extent ofland devoted on the contrary, the weather was to prove to the crop was enormous; it stretched high up exceptional in a number of respects. After a into the mountains and deep into the bogs. winter of rare mildness and a very wet spring, Further. the increasing food needs of a large and temperatures from the second half of May economically oppressed population had led in onwards soared to record or near-record heights Ireland to the replacement of superior varieties in many parts of Europe. Violent gales in the of the potato by the high-yielding but watery autumn were followed by a severe winter with 'Lumper'. which had many resemblances to a much snow. turnip. and which was grown. outside of These successive weather stages contributed, Ireland. only as cattle food. each in its own way. to the food problems The potato fields of Ireland constituted an which were to culminate in a major crisis in overcrowded slum of uniformly vulnerable Ireland in 1846-7. and we shall discuss them in inhabitants, wide open [0 epidemic disease. turn in the following paragraphs. Now that potato blight had found its way into the country-a disease far more destructive, 6.2.1 A mild winter and a wet spring more contagious and faster acting than any The very mild winter of 1845-6 over much of 41 I'otato Blight in Europe in 1845-6 western Europe (Fig. 5(b». which was Europe things were rather difTerent (Fournet. particularly marked in the months of January 1846. p.601). The sequence in Fig. 4 shows and February. was the subject of much very clearly the drift of the nucleus of highest contemporary comment, especially in farmers' temperature anomalies away ftom this area after diaries and agricultural periodicals. In an the month of June 1846. Both Ireland and exceptionally long series of temperature records Scotland had participated to the full in the hot in the Netherlands (van den 0001 (t at .• dry weather for much of June (Fig. 4(a». but 1978). the mean temperature of 5.2"<: reached for both of these countries the heat-wave broke in the winter of 1845-6 was exceeded in only before the last week in June. and while rainfall three out of 344 years. amounts were still small in gloomy. overcast In addition to being mild. the first month of conditions to mid-July. for the remainder of the summer there were few hot dry days to break 1846 was very wet; extensive tracts of Ireland the monotony of rain. often accompanied by were "saturated in water at the end of the month. The mildness of the winter persisted in thunder. London and the southeast of England also experienced a number of violent February which. however. was a generally dry month and one which held out hopes that thunderstorms as short·lived interruptions to farming land would be workable early in spring. mainly warm dry cominental weather. Townley (1847) could. however. classify the summer as a These hopes were dashed. especially in Ireland. whole in London as 'hot and droughry'. In by the heavy rains of March and April which London too June was the outstanding month persisted into May. There had been only with a mean temperature at Greenwich 3.2"C fourteen days without rainfall in Dublin in the above normal. which was only once exceeded in three month period from 24 February to 23 the next hundred years (Marshall. 1952). while May 1846. even higher values were recorded close to the city cemre. A fascinating survey of literary life 6.2.2 A summer heat·wave in London in June 1846 owes its title and The summer of 1846 was superbly hot and dty setting to this 'sultry month'. and gives some over most of Europe (Fig. 5(c); Fournet. 1846). data in passing on the high temperatures In France. where the momhs of June and July reached (Hayter. 1965). were particularly torrid (Lortet • 1846). the The heat-wave lasted longer. reached higher grapes were gathered three weeks in advance of temperature levels and was less interrupted in the usual time; in Hamburg the grain was southeast England than elsewhere in the United harvested fully a momh early. The permanent Kingdom. The end of the hot spell in Ireland snows melted on Alpine peaks. and crags were and Scotland towards the end of June was revealed on the summit of Mont Blanc which marked in London only by a very temporary the oldest inhabitants had neyer seen before. lull. and although there were periods of The heat in Russia was tropical throughout thundery rain early in July. and again. in violent June. July and August. so that it was claimed form. in the first few days in August. the that one could fry eggs on the sand in weather was quick [0 rccover irs former Archangel. One may well suspend judgement brilliance in both cases (The Times, 4 July on this traditional evidence of extreme heat. but 1846; Graham. 1847). The contrast of the July the long-period meteorological records. for weather across Great Bric.ain was [he subject of example for Vienna (Steinhauser tt aL. 1955) much comment: "In the south of England confirm the general accuracy of the record harvest began in July. and the result was solely making temperature levels of 1846 . owing to the dry weather experienced in that Along the northwest maritime border of part of the country. when Scotland and the 42 Potato Blight in Europe in 1846 nonhern pan of England were visited by daily 6.2.4 The severe weather of December 1846 showers and even rainy days in that month. for and early 1847 the crops of this country (Scotland) were as far The severiry of the cold winter of 1846-7 is advanced in June as they were in the south of illustrated in Fig. 5(d). The month of England" Qournal ofAgriculture 1846. p. 490). December 1846 was bimrly cold. with ice and snow over much of Europe. Charles Dickens reponed from Paris: "The water in the bedroom jugs freezes into solid masses from top to 6.2.3 Autumnal gales bottom. bursts the jugs with repons like small There were several exceptionally violent Atlantic cannon. and rolls out on to the table and gales in the autumn of 1846. of which at least washstands hard as granite" (Pearson 1949. two almost cenainly originated as hurricanes. p.156). A tropical storm. first noted on 12 September In England. the Thames had ice to mid in the Barbados - Martinique area. moved channel. roads were blocked by snow. and trains northwards and skirted Bermuda on 14-15 wore brought to a standstill (Dodds. 1953. September (Ludlum 1963. p. 1 32). In the p.285). following weeks a number of ships close to its In Dublin there was air frost on no fewer than track were battered. with much loss of life. 21 nights in December 1846. and on five days When the storm hit Ireland on 22 September. the temperature never rose above freezing poinL fishermen were drowned and their boats destroyed. a girl was swept out to sea. and the January 1847 was considerably less harsh. but famous ship. the "Great Britain". was driven in the last days of the month and in early ashore in Dundrum Bay on its maiden voyage. February it again became very cold. culminating with a quite exceptional minimum temperature The next major storm appears to have for Dublin of -12.2°C on the 13th. This was originated in 'the great hurricane of 1846' the crisis of the winter weather of 1846-7. but it which in Aorida was reckoned to be "the most left a legacy of recurrent cold spells at intervals destructive of any that has ever visited these until the end of April. at which time the Dublin latitudes in the memory of man" (Ludlum mountains were still snow-capped. 1963. pp.94-5. 151-3). It lashed Cuba on 10 October and New York on the 13th. The Irish brig. 'Rose of Newry'. bound from St Johns to 6.2.5 Some consequence. of the curiow Sligo. was ovenaken on 14 October by 'a fearful weather of 1846 hurricane'; it ran on for some time 'on bare The weather before and after. as well as during. poles' before capsizing in the heavy seas. The the potaro growing season of 1846 had major storm struck Ireland on 20 October and did consequences on the distress caused by blight. great damage; many ships were lost or stranded panicularly in Ireland in that year. on the Irish coast. In the mild winter of 1845-6. diseased tubers. The gale of 19-20 November was. in some left un dug in the ground or discarded as respects. the most destructive of all; when it had worthless in the furrows. survived [Q provide passed about 150 ships were floating around off numerous infection centres for the coming the Irish west coast. desened and dismantled. season's potato crop (IFJ 1847. p.2). The stormy weather on the North Atlantic The heavy rains of spring seriously retarded continued right into the early months of 1847. agricultural work in Ireland so that even in the 43 Potato Blight in Europe in 1845-6 beginning of June it could be said thar "in condition of the inhabitants. and although a many parts of the country. the poUlO planting man not easily moved. I confess myself is not completed; in other parts, not begun" unmanned by the extent and intensity of (Nenagh Guardian. 6 June). When the rains suffering I witnessed. more especially among ceased. the weather swung to the opposite the women and little children. crowds of whom extreme; it introduced one of the longest and were 10 be seen scanered over the turnip fields. most intense heat-waves known in Ireland. A like a flock of famishing crows. devouring the soil which had been saturated IOwards the end raw turnips. and mostly half-naked. shivering in of ~by reached a soil moisture deficit of over the snow and sleet. u[[ering exclamations of 90 mm four weeks later and continued at about despair. whilst their children were screaming the same level of drought until late in July. with hunger. I am a match for anything else I Everywhere the growth of the potaro crop. in may meet with here. but this I cannot stand" particular. suffered a severe check so that by the (Salam an 1949. p.308). The reason for the end of July the tubers were. at best. no bigger grave dis [Cess was the almo$[ complete than walnuts. In England the eventual verdict annihilation of the Irish potato crop in 1846. was that potato yields in 1846 were reduced as much by the aridiry of the summer as by the ravages of blight which. in that area. showed a much reduced activity Uournal of Agriculture. 1848. pp.355-6). 6.3 The Second Season of Blight In Europe The high winds of autumn increased distress The early potato crops of 1846 were scarcely in several ways. They made fishing difficult and above ground than they were carefully and often impossible. and reduced catches (Sociery continuously scanned by anxious eyes for the of Friends. 1852. p.409); in a number of cases. slightest signs of disease. So many blighted boats were lost and fishermen drowned. Over tubers had been discarded during the previous the North Atlantic the recurrent gales harassed harvest and so many of the deliberately planted and delayed the food ships bound for Ireland seed potatoes had in them the germ of disease. (Distress correspondence 1846. p.218; IFJ that early signs of blight were inevitable as soon 1846. pAil); along the Irish coast they as the weather became in the slightest degree hampered relief operations (Distress favourable to its development. In fact a lengthy correspondence 1846. pp.92. 10 I. 110. III. spell of blight weather was registered at Dublin 189. 198.201.205). on May 22-3. to be followed by a shorter spell on June 8-9 (Fig. 13). The disease showed its The severiry of the winter of 1846-7 hindered teeth sharply in early potato crops on the coasts the relief efforts of the Quakers and others of southern Ireland and southwest England (Society of Friends 1852. pp.l48-9); at the same (Milne. 1847. p.259; GC 1846. p.390). time the bitter weather struck one final blow at the starving millions in Ireland. whose By reason of the hot dry weather which condition at the end of the year may be prevailed for much of June. the disease made illustrated by a quotation from a letter written limited progress at first and was reponed from by a relief inspector to his superiors on only a few places. often in the form of stem Christmas Eve. 1846. He wrote from a parish in lesions as is characteristic of blight in a dry year. the west of Ireland where relief work had been A series of blight weather spells. none oflong suspended because of an act of violence: "I must duration but of appreciable cumulative effect. again call your a[[ention to the appalling state occurred in Ireland in the period 22 June - 10 in which Clare Abbey is at present. I ventured July (Fig. 13). at a time when the weather in through that parish this day to asceruin the Brussels was almost continuously unfavourable 44 PotalO Blight in Eurol'" in 1846 to the disease. The reason is reflected in the yield was reduced because of drought. maps of mean atmospheric pressure for July in A curious incident illustrates that. while the 1845 and 1846 (Figs. 6 and 7). The area of low majority of people on the continent rejoioed in pressure centred over the North Sea in the the health of their potalO crops. the occasional earlier year was the origin of the poor weather food speculalOr. poised to profit from public which was shared by all the countries of alarm. was chagrined at the failure of the disease northwest Europe in July 1845. In 1846. to cause a second panic. Two prisoners were however. the North Sea area was dominated by brought to trial at Breda in the Netherlands on a ridge of high pressure. and the region of 24 July 1846. having been caught in the act of disturbed weather was largely confined to sprinkling acid on the leaves of potato crops. in Ireland and Scotland. an drott to deoeive the country people that the By mid-July the potato disease was resultant black spots were caused by the onset sufficiently obvious in Ireland 10 persuade the of blight (Umerick Chronicle. 1 August 1846). Dublin correspondent of the London TImes to The relative distribution of blight damage in abandon his sceptical attitude about the 1846 (Fig. 13) is what we should recognise reappearance of the disease: "I regret to say that nowadays as characteristic of a season in which the apprehension of a failure to a considerable the main periods of blight weather were extent in the crop of this year appears 10 be only associated with Atlantic depressions moving too well founded" (The TImes. 11 July). About generally IOwards the northeast on the fringe of the same time the disease manifested itself in a continental area of high pressure. In contrast Scotland. fully two months earlier than in the to the abnormal pattern of the previous year previous year (Milne. 1847). and later was (Fig. 11). the chan of blight progress had fallen reported from the Highlands and Islands. into what was to become a familiar mode. including the Orkneys which had escaped in the previous year (GC 1846. pp.595. 647). 6.5 The Destruction of the Irish Potato Crop 6.4 Meanwhile. on the Continent..• in 1846 It was already clear by mid-July 1846 that the An abstract of the country repons received in geographical distribution of blight damage in the week ending 25 July 1846 and preserved Europe was going to be radically difTerent from with the papers of the Relief Commission in that of the previous season. W'hile alarm was Dublin. graphically illustrates the rising tempo mounting steadily in Ireland and Scotland. it of the blight attack in that month. From all fell away on the neighbouring continent where over Ireland the alarmed reports poured in - as the dry hot summer continued unabated. the "disease making daily progress". "early crop disease made little progress except in isolated completely destroyed". -early crop and Luml"'rs areas and gradually disappeared as a subject of withered". "great panic". The Grand Jury of the discussion in newspapers or even in learned city of Cork respectfully directed attention. on journals. 25 July. to the "iml"'nding calamity". The broad features of the final distribution of The crowning blow was not long delayed. On damage done by potato blight in 1846 are July 26 - 27 there was a short spen of blight shown in Fig. 14. The potato crops in areas of weather. and then. in the last four days of the the earliest and heaviest attack in 1845. i.e. month. the most sustained period which those of Belgium and Holland were now occurred in the years 1845-7 (Fig. 13). The vittually free of damaging disease in a season synoptic situation on 31 July 1846 (Fig. 10) has which afforded only the scantiest of blight been chosen as representative of this period and weather (Fig. 13). although here too the final 45 Pot.to Blight in Europe in 1845-6 Fig. 14 Approximate distribution of pouto blight damage in western Europe. 1846 46 Potato Blight in Europe in 1846 shows a broad belt of maritime tropical air all hopes of future profit by thes. means were sw •• ping north.astwards ov.r Ireland and gon •. But my own losses and disappointments. Scotland. wh.re it gave ideal conditions for th. deeply as I felt them. were soon m.rged in th. final onslaught of blight. but with hot dry general desolation. misery and starvation which w.ath.r e1s.wh.r•• brok.n only by an now rapidly affected th. poorer classes around occasional thund.rstorm. Not. th. contrast in m. and throughout Ireland" (Trench. 1868). Fig. 13 b.tw •• n th. conditions which continued right through August in Dublin and th. scanty impact of blight weath.r in July and August in Brussels. Virtually th•• nrir. potato crop of Ireland 6.6 Loss •• Caus.d by Blight in Ireland in w.nt down in ruins in th.last week in July and 1846 th. first two weeks of August 1846. In a w.lI Under normal circumsrances. destruction of known I.rr.r dat.d 7 August 1846. Fath.r potato haulms by 1 August would cause a loss Theobald Mathew described the chang. which of abour 50 per cent of the .xp.cted yield took place in a singl. week: "On th. 27th of last (paragraph 2.4. I). But 1846 was far from being month I pass.d from Cork to Dublin and this a normal year: th. plan ring of th. crop had doomed plant bloomed in all th. luxuriance of been much delayed b.cause of h.avy and an abundant harv.st. Returning on th. 3rd continuous rainfall. and drought had later instant. I beheld with sorrow on. wid. waste of radically slowed down th. d.velopment of purrifying v.getation. In many places the tubers so that they were abnormally small wh.n wr.tched peopl. w.re seated on the fences of blight destroyed th. planrs. th.ir decaying gardens. wringing their hands Derailed surveys carried out at the tim. and wailing bitterly th. destruction which had showed that th. average loss was as high as 90 left th.m foodless". p.r c.nt. so that of a y.ar·s supply of food. th. In 1845. upland potato fields had stood up residue would last only betwe.n four and six reasonably well to the disease. but it was not so weeks. In Scotland and in pam of Ulster wh.re in th. warmer summer of 1846. Steuart Trench. oars still made up part of the popular diet. there a land agent in the Irish midlands. had planted was some hop. for survival until relief cargoes potatoes on some 50 hectar.s of r.c1aimed of maize arrived from North America. but for bogland high up in th. Slievebioom mountains. th. majoriry of th. poor Irish ther. was no hope On 1 August. he confirm.d for himself whatever. Ev.n the lull in th. severiry of blight rumours that the disease was striking fatally at in th. dry w.ather of 1847 (Fig. 13) brought lowland crops. but when h. rod. up to inspect littl. relief, for th. acreage sown in potatoes in his mountain crop. he was relieved to find it "as that season was only on.-tenth of normal. and luxuriant as .ver. in full blossom. the stalks by then th. ravages of famine fever had b.en maned across each other with richness. and added to thos. of starvation. Within a coupl. promising a splendid produce". A week later th. of years there was an abrupt fall in the Irish pictur. had radically changed. "On August 6. population due to death or Right of nearly two 1846-1 shall not readily forget th. day-I million souls. and this was followed by a rod. up as usual to my mountain property. and century of continuous haemorrhage due to my feelings may b. imagined when. before I emigration (Fig. 15). saw th. crop. I smelt th. fearful stench. now so well known and recognised as the death-sign of .ach field of potato.s .... I saw the crop fast disapp.aring and melting away under this fatal diseas •.... My plans. my labour. my £3.000. and 47 Potato Blight in Europe in 1845-6 , B.18 , ~ __ - 8.3 _pprox. \ \ \ ~7 \ Z Population of o Ireland ~ oJ, Population of England and Wales 1821 - 1881 ! zll ..-o J2 Fig. 15 Population changes after 1821 in Ireland and England - Wales 48 CHAPTER? SUMMARY OF CONCLUSIONS 7.1 Blight in 1845 favourable weather conditions have occurred in All the evidence suggests that it was the search some modern y"ars. The main reason why the - which must now, in retrospect, be seen as an impact of the disease on the crop was incautious eITort-for a remedy for a lesser abnormally great was that many of the most ailment of the potato which opened the popular pouta varieties grown at the time floodgates for the entry into Europe of what proved to have no resistance whatever to the was to prove itself a far greater evil. potato new disease and were soon to drop out of blight. In.n eITort to reduce losses in the cultivation. The losses of crop in Belgium and potato crop caused by dry rot. ond to counter Holland in 1845 were very heavy. of the order the consequent food problems omong the poor. of three-quarters or seven-eighths. the Belgian government decided to import fresh The spread of the disease. not only in the potato varieties from the Americas. and these direction of the prevailing winds but also were tried out as field crops in West Flanders in towards the west. has been shown to be 1844 ond 1845. It is highly probable that the consistent with the weather patterns of the germ of potato blight was introduced in these season. and the mechanism for the windbome imported stocks. either directly from the Andes transport of blight spores across the English region of Peru· Bolivia. or indirectly via North Channel to be closely analogous to that of foot America where the disease had already appeared and·mouth disease in recent years. The failure in 1843. of blight to reach northern Scotland in 1845 The approximate dates on which potato reflects the low temperatures of that summer. blight was first reported in diITerent partS of Europe in 1845 appear in Fig. 1 I. This shows the earliest impact of the disease in West 7.2 Blightin 1846 Flanders in I.te June. and its gradual extension The second season of the blight invasion in to reach Ireland. Scotland and Scandinavia close 1846 showed a very diITerent distribution of to harvest time. disease. The summer of 1846 was mainly dry An analysis of the weather data for the and hot on the continent and the potato crop growing season of 1845 shows that conditions there-as well. indeed. as in the south and east were indeed favourable for the development of of England-sufTered much more from drought the disease to epidemic level in that year. than from blight (Fig. 14). Meanwhile. How('Ver, they were not uniquely so; even more depressions skirting the northwest border of the 49 PoUto Blight in Europe in 1845-6 continental anticyclone brought vety different blow to the starving millions. conditions to Ireland and Scotland. where the The potato yield in Ireland in 1846 was no weather favoured a renewed epidemic of blight. more than 10 per cent of normal. and hence The severity of the attack was once again not little worse than in parts of Belgium in 1845. due to anything unique in the frequency of However. the population which had to bear the blight weather; more favourable seasons for loss was immensely more vulnerable in the disease have occurred later. Part of the damage conditions of the Irish potato economy. where was caused by the complete susceptibility of the grain foods were no longer part of the normal poor man's "Lumper". but even more was due diet of the mass of the worki ng population. to a remarkable sequence of weather abnormalities. both within and outside the The situation in Ireland in the 1840s. with its 1846 growing season. which intensified the rural population heavily dependent on a single consequences of the plant disease. crop. can be clearly seen in retrospect as precarious to the point of being ripe for If a malevolent fate had set its mind to the disaster. The arrival of the potato disease and destruction of the Irish people. it could scarcely the wc:ather, which in several successive years have devised a morc disastrous sequence of favoured its development. was the spark that weather phenomena than that which marked produced the tragedy. cruelly exposing the the year 1846. inherent weaknesses of the socia-economic The nearly unique mildness of the winter of structure of Ireland at the time. Nevertheless. 1845-6 permitted infected tubers from the in the light of modern climatic and agricultural 1845 crop. which had been abandoned in the knowledge. and studies such as the present one. fields or discarded as worthless in the furrows. we can say that foresight and precautionary to live: on [0 become infection centres for the planning-on an international scale where new season"s potato crop. necessary-should be able to mitigate. and sometimes largely avert. the effects of such A spring of continuous heavy rain seriously visitations by weather and disease. delayed the planting of the new crop. and was followed by an unprecedented heat-wave in the For this reason the story of the Irish poUto months May-June which so slowed the bulbing famine of 1845-7 may have useful lessons to of the tubers [hat they were no bigger than teach in conneaion with modern food crises, marbles when blight wiped out the plants in the especially in Third World countries. and in early days of August. Violent autumnal gales particular to point the need. before anything restricted fishing. retarded food ships bound else. to recognise the inherent vulnerability of from America and hampered relief operations the population as the prime cause of disaster around the coasts. A winter of great severity and to take steps to remedy it. and much snow in 1846-7 was the final bitter 50 REFERENCES Bergman. M .• 1967. The potato blight in the 1971. Possible wind transport of coffee l..frust Netherlands and iu social consequences. 1845- across the Atlantic 0=. Natu". 229. 500-01. 47. Intanatioruzl Rrvinu of Social History. Xl!. Bourson. p.. 1845. Expou analytiqw '" divffln 390-431. opinions sur In causrt probabln '" 14 maWi. drt Board of Admiralty. London. 1848. 1849. pommn d. Uru. prluntl .t la commission Afap.tical and M.uorological Obs""ations mad. institutl. pr~s du MinistIT, d, I'lntlri,ur. at th. Royal Oburvatory. G"mwich. in th. y.ar Brussels. 1845.1846 (G.B. Airy. Astronomer Royal.) Clouston. e.. 1861. M.t.orological obs""ations Bourke. P. M. A.• 1955. The forecasting from takm at Orknry; with r=arh on th, climau. weather data of potato blight. and other plant London (Eyr< and Spottiswood.). diseases and pests. WJ.fO Hchnical Nou No. Cooper. E. J .• 1847. Observations on the 10. Geneva. potato disease. with an inquiry into its possible Bourke. P. M. A .• 1956. Agricultural connexion with atmospheric phenomena. meteorology: A report prepared for the Proardings of th, Royal Dublin Soci.ty. 83. government of Chile. Uniud Nations R'P0r/ No. Appendix No. IV. xv-xxvii. TAAICHII2. Cox. A. E. and Large. E. C .• 1960. Potato Bourke. P. M. A.• 1957. The use of synoptic blight epid.mics throughout the world. weather maps in potato blight .pid.miology. Agricultural Research Service. US Department Irish M.uorological Sn-vic •• Hchnical Nou No. of Agriculture. Agricultural Handbook No. IN. 23. Dublin. Washington De. Bourke. P. M. A.. 1964. Emcrgence of potato Crosier. w.. 1934. Studies in the biology of blight. 1843-46. Natur•• 203. 805-8. Phytophthora infrstans (Mont.) de Bary. Cornell Bourke. P. M. A. 1968. The use of the potato Universiry Agricultural Experiment Station. crop in prefamine Irdand. Journal of th. M=oirNo.155. Statistical and Social Inquiry Sociny of /r.14nd, Distress Corrcspondencc.1846. XX!, 72-96. Correspondence explanatory of the measures Bourke. P. M. A.• 1969. Potato late blight in adopted by Hcr Majesty's government for the Canada in 1844-45. Canadian P14nt Diuau relief of distress arising from the failur< of the SU""1 (Ottawa). 49. 29-31. potato crop in Irdand. HC 1846 (735). xxxvii. 41. Bourke. P. M. A.• 1971. Disease r 51 Potato Blight in Europe in 1845-6 Dumortier. B. c.. 1845. Observations sur la Lortet. p.. 1846. Rapport sur les travaux de la c10que des pommes de terre. Bul/nin de commission hydrom~trique en 1846. AnTllZ"s l'AcaJimi, Royak tks Sdmm tI &lks-ullm tk tk '" Sodltl d'AgricultuTl! tk Lyon IX. 714-9. Brwulks, XII (Pt ll). 285-99. Ludlum. D. M .• 1963. Early Amtrican Fournet. J.• 1846.Noticc sur les orages et sur la Hurricanes: 1492-1870. Massachusetts. pluie de terre de r automne 1846. AnTllZks tk '" Manley. G.. 1974. Central England Sodltl d'AgricultuTI! tk Lyon. IX. 593-693. temperatures: monthly means 1659 to 1973. G C Gartknn-s Chronick. London. Quarur/y Journal of the Royal Meuorological Graham. F. J .• 1847. The Potato Diuau. Sodety. 100. 389-405. London. Marshall. W. A. L. 1952. A Cmtury ofLondon U-'t-ath", London. Harting. p.. 1846. kch",hes sur'" natu" tI ks caum tk '" ma/adie tks pommes tk urre en 1845. MB Aloniuur Beige. Brussels. Amsterdam. Milne. D .• 1847. Oburvarions on the probab" Hayter. A.. 1965. A Sultry Month. London. cauu ofthe foilu" ofthe potato crop in 1845 and Hogg. W. H .• 1970. Weather. climate and plant 1846. Edinburgh and London. disease. 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Th, History and Social bifluenu ofthe Potato. Cambridge. 52 Semal. J •• Jolr. P. and Lamr. D .• 1983. Townley. J.• 1847. Tht DistllSts. >n"atio1l J.:~piMmie de "maladie des pommes de terre' and CuI,"" oftht POt4to. London. cau~e en Europe en 1845 par Ie Prytophthora Trench. W. S .• 1868. &alitits of !rish Lift. inftst4m (Mont.) de Bary: I.. faits et les auteurs. London. Annaks tU Gnnbloux. 89. 79-99. van den Dool. H.M .• Krijnen. H.J. and Societas Meteorologica Palatina. EphnnmtUs. Schuurmans. C. J. E.• 1978. Average winter Mannheim. 1781-1792. temperatures at De Bilt (The Netherlands): Society of Friends. 1852. Tramactions of tht 1634-1977. Climatic Changt, 1,319-330. Cmtral hlit[Committtt oftht Sodtty ofFrimds V"sseeing. S•• 1845. £migt opmtrkingm tI!r ukt during tht Famint in !"land. Dublin. dtraard4pptlzitktt. Amsterdam. 1845. Steinhauser. F.. Eckel. 0 .• and Sauberer. F.. von Martius • C. F. p.. 1842. Die Kartoffel 1955. Klima und Bioklima von Vienna. Wim. Epidemie der lenten Jahre. oder die Stockf:iule Stevens. N. E .• 1933. Phytopathology - the und Raude der Kanoffeln. Munich. dark ages in plant pathology in America: 1830- Whyte. R. 0 .• 1963. The significance of 1870. Journal of tht Washington Acadtmy of climatic change for natural vegetation and Sdmm 23.435-46. agriculture. In: Changts of Climatt. UNESCO Todd. F. A .• 1961. The occurrence of blue Arid Zone Research Series. xx. 381-6. mold of tobacco in West Germany. Switurland. Unger. F.. 1833. Dit Exanshnnt dtr Pjla= France and other European countries. Plant Vienna. pp. 422. Distast Rtportn; 45.319-26. Bibliographical details of sources of meteorological observation data used are given in the Appendix to this report. 53 APPENDIX LIST OF METEOROLOGICAL OBSERVATION SITES AND DATA SOURCES The records used in mis study included: NORWAY Alten Observations made at a British ICElAND expeditionary station. at 700N near 23~0·E. Eyjafjordur. on the north coast. near 65.5°N operating from IS39 onwards. Instrument IS.I"W. Weather diary without instrument measurements are included. baromcuic measurements. from the last months of the pressure: in mm, tcmpc:racurts in DC. Register in daily record maintained (with some changes of me Meteorological Office Archives at Bracknell. site) by the parsons J6n J6nsson. father and England. son. from 1746 to IS46. ending a few days before the latter's death in August IS46. Trondbeim (63.5°N 10.4°E). Once daily Copied. the difficult handwriting deciphered. observations. including barometric pressure in and lUndly translated. by Sjofn Kristjansd6ttir. Paris inches and lines. tcmpC'uturC's in OR, as from me manuscript in me Icelandic archives in printed in the newspaper -Adccsscavisen-. Reykjavik. Kindly supplied by the University Library. Trondheim. StylJdshoImur. on me west coast. near 65.1 ON 22.S"W. Meteorological observation register. Klepp. or Grude. near Varbaug (5S.SoN lUndly supplied by the Iceland Weather Bureau 5.6°E). in Jaeren. S.w. Norway. This place is in (Vedurstofa Islands). The observations begin in • broad agricultural lowland province near the September IS45. Instrument measurements are coast between Egersund and Stavanger. included from November IS45 onwards. Notes from a farm weamer diary at Grude covering the years IS0S to IS50. printed in a Norwegian-language text on Jaeren. its FAEROE ISlANDS economy and communal development from IS14 to 1914 by the lens mann (sherif!) M.K. Observations. including some instrument Grude. published as "Jaeren IS14-1914" at measurements. occasionally available when Sandnes (Ingvald Dahles Forlag) 1914. Danish naval ships were in harbour or patrolling waters near the islands. Ships' logs Besides summaries of the: seasonal weather lUndly supplied by the Danish Meteorological each year. reports of the crops. including a "dry Institute. Copenhagen. rot" of the potatoes increasing strongly in me 54 Appendix autumn of 1845 and continuing for several FINLAND yean. though less in 1847 than in 1846. Helsingfotl (now known internationally outside Finland by its Finnish name. Helsinki) Christiania (now Oslo). (59.9°N 10.8°E 600 10·N. 24°57·E. Observations three times approx.). Five times daily observations. every hour made at the Magnetic and including barometric pressure in Paris inches Meteorological Observatory. under the and lines, temperatures in OR. wind direction direction of the professor (Nervander) of and force. and cloud details (type and amount). physics at the University. The observations published with a German language t 55 Appendix instruments. their history and corrections island of Bornholm, positions in port or applied. and their exposure. kindly supplied by patrolling near the south and east coasts of the Danish Meteorological Institute. Iceland and near the Faeroe Islands were Copenhagen. included, also on voyages between either Denmark or Iceland and the mouth of the Ringkebing (actually at Stadil. near (English) Channel on voyages to or from the Ringk0bing). near the west coast of Jutland. A East or West Indies. On most days. manuscript register (kept near 5G.2~ 8.2·E) observations made on board Danish vessels in in Danish. with three times daily temperature port at Altona (then .. Danish naval base, but measurements in 'R, once or twice daily reports now part of Hamburg) in the Elbe were of wind direction. notes on the occurren~s of available. rain, thunder and occasional notes of extremes or a barometer reading. kindly supplied by the Danish Meteorological Institute. Copenhagen. Traneberg. on the island of Sams". Relevant portion of a manuscript register (in Danish) of IRElAND meteorological observations. kept at a point Dublin, 53°22'N, G021·W. Meteorological 55°S0'N IOo37'E, including twice daily observations made three ro five times a day (in temperature measurements in OR, three times different years) at the Ordnan~ Survey Offi~ daily baromcuic pressures in various units in Phoenix Park. Dublin. collected in a volume (sometimes in millimetres), rainfall measured covering the years 1829 ro 1852 (edited by on~ daily in Paris lines. (The register starred in Captain Cameron, R.E .• under Lt.Col. H. 1838, when all measurements were in Paris James. ER.S .• Superintendent of the Ordnan~ lines and OR .) Wind direction and strength (on Survey of Ireland), published by Alexander a scale from 0 ro 4 or 5) reporred three times Thorn and Sons. Dublin 185G for Her daily. Kindly supplied by the Danish Majesty's Stationery Office (G03pp). The Meteorological Institute, Copenhagen. observations include barometric pressures in inches and thousandths (with temperature correction applied, as usual in the sources here Danish Naval Ships at Sea. Observation. used), temperatures in OF, also daily maximum transcribed from twelve ships' log •• usually and minimum temperatures, dew point every 4 hours, and including the ship's position. temperatures (from June 1841 onwards), wet direction and strength (convened ro Beaufon bulb temperature (from 1842). rain gauge force) of the wind, weather (in leuer code). measurements, wind direction and its strength cloud cover (convened to eighths of the sky measured by various (usually pressure-plate) covered), temperatures in OR. and barometric anemometers. pressure mcasuremenu in Paris inches. lines and t 5G Appendix Markree Castle. Co. Sligo. near 54.2°N. Makerstoun. near Kelso. 55°34'N. 2°31'W. 8.6"W. Monthly values of temperature each Hourly observation. (on Sunday. not every year from 1842 to 1863 and of rainfall from hour). including barometric pressure reduced to 1833 to 1863. printed in the QUlZrurly Jourruzl O°C. temperature. (dry and wet bulb). wind of Iht Royal Mtltorological Sontty. 10, pp.l58. direction (32 points of the compass) and its 161. 1884. Further details of the weather at force given a.s the maximum pressure measured Markree Castle are given in a paper by E. J. on a pressure plate in 10 minutes and in the Cooper (see references). hour. cloudiness given in tenth. of the sky covered. and detail. of the rype. of cloud Portarlington. 53.ZON. 7.2"W. Daily rainfall present and the direction from which they were measurements throughout 1845 and 1846. moving in each of the main levds (low. middle from the· Dublin Mtdical Pms". vols. XIII· and high) represented. a.s well a.s remarks on the XVI. 1845-1846. weather. The observations; for 1845 and 1846. made at the Makerstoun Magnetical and Athlone. 53.4°N. 7.9"W. Monthly rainfall Meteorological Observatory belonging to measurements throughout the years 1845- General Sir Thomas Makdougall Brisbane. 1848. also notes of big rises in the levd of the Bart. F.R.S .• F.R.A.S .• President of the Royal River Shannon in July, October and December Society of Edinburgh, and edited by John Allan 1845. and in May. November and December Brown. Director of the Observatory. were 1846, and of big falls in the levd of the river in published in full in Part 1 of the Trarwutions of February. March. April and August 1845 and tht Royal Sodtty ofEdinburgh, vol.XIX, in 1849 February. May. June and September. 1846. by Robert Grant and Son. Edinburgh. wteriy winds were noted a.s prominent in July Table. of statistical results. including daily and September 1845 and winds in June to NW and weekly means of temperature and water August of that year. Source: Procttdings of Iht vapour pressure. extremes. ranges, Royal/rish Acadtmy, vol.lV (1850). Appendix measurements of evaporation and so on. were VI. pp. Ixix to Ixxiv. published in rart II of the Trans.Roy.Soc. Edin.. vol XIX, in 1850. lJmerick, near 52.7°N. 8.6"w. Yearly rainfall totals for the rea" 1841 to 1850 inclusive. Sandwick. Orkney. near 59°7'N. 3°21'W. Monthly mean values of the air temperature (OF from 1833 to 1859 (and from 1827 to 1832 at the manse at Stromness) and of barometric pressure in inches from 1839 to 1859. and SCOTI.AND monthly rainfall totals from 1841 to 1859. Ballimore. beside Loch Fyne. near together with the number of day. each year Lochgilphead. near 56.0"N. 5.4"w. Once daily from 1827 to 1859 that the wind blew from measurements of barometric pressure in inches each direction (8 points of the campa.ss) or was of merrury. and of temperature OF. usually also calm. and more details including temperature the wind direction, in a manuscript register. of the sea and soil temperature at 12 inches with remarks on the weather twice or more depth for the year 1827. printed in times a day and occasional rainfall • "ftuorological ObStrValions ,a/un at Orltnt] measurements spanning several days catch. wilh Rnnarla on Iht Climau". by Rev. Charles from the archives of the Meteorological Office. Clouston. published in London by Eyre and Brackndl, Berkshire (England). Spottiswoode. 1861. 57 Appendix ENGL\ND summaries of the weather each day - a very neat Whitehaven. on the coast of Cumberland (near and well written record. 54.6°N. 3.6°W). A printed sheet giving monthly mean. and high ..t and low ..t values. Tutbury. Staffordshire (near 52"52·N. of barometric p«ssure (in inches) and 1°42'Wj. A well written diary of the weather. temperatures (OF). as wdl as rainfall totals with once daily reports of wind direction. (inch.. and thousandths). amounts of snow and written as notes on the blank pages of The monthly readings of an evaporation gauge (in Farmer's A1manack. covering the months June inches). as well as monthly summaries of the to September 1845. weather. all for 1845. and annual values of all th ... items for the previous three years. 1842- Cornwall Monthly values of the barometric 44. printed under the title "Th~ Mmo",logy of pressure. dry and wet bulb temperatures at WhiuhlZvm" by George Irwin. Herald Office. 9a.m .• 3p.m. and 9p.m .• of wind direction and Whitehaven: obtained from the Meteorological force. of rainfall. of mean cloudiness (in tenths Office Archive". Brackndl. as were all of the of the sky covered). numbers of wet and dry following items. days etc •• at Hdston. Cornwall (5007·N. 5°18'Wj, and of some of these items at Newcastle-upon-Tyne (approx 55°N. 1.6"W). Falmouth. in 1845 and 1846. printed in the Three times daily observations of barometric Annual Rrports ofth~ RoyIZI CornwlZll Polyttchnic pressure (reduced to O°C). temperatures (dry Soci~ty. Falmouth U.Trathm). and wet bulb). and wind direction. together with the daily maximum and minimum Modbury. near Plymouth (near 50.5°N. temperatures. rainfall amounts. and a summary 3.9"W). A meteorological journal. begun in of the weather. reprinted by the literary and 1788 and continued to 1866. giving once daily Philosophical Society from the N'wCIZII/~ temperatures, wind direction observations, and jOllnuzl a summary of the weather. Kendal (54.3°N. 2.75"W). A rather untidy Sidmoutb (near 50.7°N. 3.2"W). A manuscript. but meticulously kept record in meteorological regi"er with daily morning and good handwriting of three times daily afternoon readings of barometer and observations of the barometer. once daily thermometers. usually also wind direction and a readings of an unidentified form of hygrometer descriptive indication of irs strength. notes of and of the wind direction at noon. together when rain was falling. and a description of the with summary descriptions of each day's weather in a neatly written manuscript. weather. Isle of Wight (near 50.5°N. 1.25"W).- Monthly Pontefract. Yorkshire (53.7"N. 1.3OW approx.). mean values of temperature (OF). barometric Daily readings of maximum day and minimum pr 58 Ap~ndix temperature, and wind direction and force, with readings. also a hygromeler (de Saussure ~. a careful descriplion of the daily wealher and giving rdarive humidiry). and wind direction Slale of Ihe sky. and monlhly 10lals of rainfall and force. as well as once daily measuremenrs in and evaporalion. in a beaulifully wri((en millimerres of Ihe rain and snow fallen. and manuscript. dcscriprions of Ihe s(ale of Ihe sky and wearher. Supplied by Ihe InsUCUI Royal M~I~orologique. Greenwich. 51 "29'N. 0°. Observarions. every Brussds. 2 hours. of baromerric pressure (correcled 10 O°C). dry and wet bulb temperatures. wind direction. occasional measurements of wind THE NETHERlANDS srrenglh by pressure-plale anemomelers. and Den Hdder. 52"58'N. 4°45'E. Copy of Ihe descriprions of Ihe wealher. cloud amounl. and exrremely nea! manuscript regiSler of frequenrly dew point values. as well as daily observarions at this point on the coast in Ihe measuremenlS of rainfall by Ihre. rainguages. no((hweSl of Holland, wilh observarions Ihree prinled in Ihe • Magrutical and Afmorological rimes daily of baromerric pressure in Oburvations mad. at th. Royal Oburvatory, millime"es (corrected to aOC). temperature Grunwich". Published in London (Palmer and (0C). rdarive humidiry, vapour pressure (mm). ClaYlon) in 1848. by order of Ihe Board of wind direction and speed (in dis per second). Admiralry (George Biddell Airy, M.A .• and Slale of the sky and wearher. as well a. Asrronomer Royal). maximum and minimum temperature and measured rainfall once a day. Also ride levd Observarion regimrs for 1845 and 1846 were measurements. Supplied by the Royal also received for Uffington (Lincolnshire). Nelherlands Meleorological [nsrilule. as were Welbeck Abbey (No((inghamshire). Benefield all Ihe olher DUlch observarions. (near Oundle. No((hamplOnshire). SwaIIham Bulbeck (Cambridgeshire), Wycombe and Groningen (in Ihe nOrlh easlernmost part of Burnham (Buckinghamshire). Cobham Ihe country) near 53.25°N 6.5°E. Tabulared (Surrey). Uckfield (Sussex). and (WO addilional observarions of lemperarure (OC). wind poinrs in London (one of Ihem being Ihe Royal direction and wearher. and once daily rainfall Ho((icullural Gardens. Chiswick). measurements. Leeuwarden. norrh Friesland. 53.2"N. 5.8°E approx. Monlhly summaries of Ihe wearher. BELGIUM wilh nOles of Ihe monrhly mean and extreme Brussel •• 500 50'N. 4°20'E. Observa!ions barometric pressure and temperature readings published in Ihe Annaln d. /'Ob",."atoi" Royal wilh dates of the occurrencc:s. prevailing winds. and presumably made ar Ihe observarory; and monthly rainfall lorals. printed in DUlch Ihough the baromeler heighl above sea levd language. (56.56 metres) differs from that at the modern sulion there (104m). and it is possible. Zwanenburg. in cemral Holland. 52°23 'N. Iherefore. thar Ihe sile in 1845-6 was at Ihe 4°44·E. Copy of Ihe observarions of barometric headqua((ers of Ihe Royal Academy of Science pressure in Rhineland inches and lines (1 (as had been Ihe case in Ihe previous cenrury). Rhindand inch = 26.2mm). lem~ratures ("Fl. Readings of Ihe inSlruments at founeen wind direclion and wearher. observed Ihre. different hours of Ihe day and night. including times daily and monrhly rainfall 10lals (in dis). barometric pressure in millimetres (reduced 10 in Ihe original manuscript regiSler. supplied by O°C). temperalure (0C). wet and dry bulb the Royal Nelherlands Melcorological [nSlilule. 59 Appendix GEru.iANY "Btobachtungm dtl "ftttorologischtn Altona. on the River Elbe. now part of ObuTVatoriums auf dtm Hohtnpdsstnbtrg von Hamburg. near 53.5"N. 9.8°E. Observations 1792-1850. l Supplmuntband zu tim Annaltn supplied by Danish ships in what was at that dn- MiinchmtTSkmwartt". Munchen 1851. time a Danish naval station (see under Denmark). Frankfurt am Main. near 50.1"N. 8.rE. Three times daily observations of barometric pressure CZECHOSLOVAKIA in Paris inch(s and lines. temperature in OR. Prague (Klementinum). 50005'N. 14°25'E. wind direction and weather. as well as daily Once daily values of barometric pressure in maximum and minimum temperatures from a millimetres. observed at 14h .• daily mean thermograph and the height of the River Main temperature. also the daily maximum and in Rhineland in feet and inches. as well as some minimum, wind directions and Beaufort force, further notes on the weather day by day. and cloud cover (in tenths of the sky covered) Supplied by the DeutsCher Wwerdienst. also at 14h .• and the daily rainfall totals. as tabulated in the twO volumes of""ftttorologickJ Dessau. in the Dukedom of Anhalt. central PozorovJni v I'rau-Klnntntinu: I 1775-190fT Germany. near 57.8"N. 12.25°E. Three times and "/I 1901-1975". published in Prague 1976 daily reports of barometer readings in Paris by the Hydrometeorological Institute. which inches and lines. temperatures in OR. and brief kindly supplied the volumes. reports of the weather daily. copied from the Relative humidiry observations (presumably newspaper Dessauisches Wochenblatt; supplied at 14h.) arc included in the tabulation from by the Deutscher ',);'etterdienst. 1845 onwards. Certain details of the instruments and (hdr exposure are given in a short introductory teX[ in voU in Czech. Berlin. ncar 52.5°N. 13.4°E. Daily mean Russian and English. temperatures, tabulated, covering the years 1781 to 1919. for the months of June to September. supplied by the Deutscher '\(;'cncrdienst. Three times daily observations of barometric POUND pressure in Paris inches and lines (reduced to Warsaw. 52"13'N, 21°2'E. Four times daily 100R or 12.5°C). temperature (OR). vapour observations made at the Asuonomical pressure (in lines). wind direction and force (on Observatory of barometric pressure in the 5-point scale defined by the Societas millimetr... temperature (0C). wind direction. Meteorologica Palatina in the previous and stale of the sky and weather, and once daily century). cloudiness (in fourth parts of the sky values of relative humidity and measured covered) and brief coded descriptions of the rainfall. also monthly summary values. weather at the high-level observatory photocopied from printed tables. together with Hohenpeissenberg. near Munich, c. 1052 a translation of the key words from Polish into metres above sealevel were also supplied by the English, were kindly supplied by the Institute Deutscher Wellerdienst. These dara were of Meteorology and Water Management. published under the authorship ofJ. Lamont in 'X'arsaw. 60 --~------ Appendix RUSSIA observations of barometric pressure (reduced to St Petersburg, 59°57'N, 300 17'E. Hourly O°C), temperature and wet bulb temperature observation. throughout the 24 hours, of (in a column headed "Hygr.") in oR, and wind barometric pressure, reduced to 13.5°R direction and force (on the usual 0-5 scale, (I6.9°C) (the printed figures being in "half standardized by the old Societas Meteorologica lines", Le. twenty· fourth parts of an English Palatina in the previous century) and, in inch), temperatures in DR, state of the sky (by extremely abbreviated form, a note of the symbols) and weather (in French language), and weather or sky cover (Rg. = Regen/rain, W = wind direction, the force also being indicated wolkig/cloudy, tr overcast, h by abbreviations (C = calme, fb = faible, t.fb = trubl = probably = tres raible, m = moderate, f = fort, t heiter/clear) and additional notes in a Remarks . f probably = tres fort), also measurements of column (e.g. Gew. = Gewitterlthunder, Wtte. rain and snow fallen twice daily at 8 and 20h, probably meaning Wetterleuchtenllightning), and note. in the Remarks column of the times printed in an official volume" J,f,uorol<>gilCh, of occurrence and other details of the weather, Brobachtungm an drr 1,.1,. Surnwartt in Wim printed in the 'Annuair~ J,fltlorologiqu, ,t von J 775 biI J 855", by Carl von Linrow & J,fagnltiqu~ du Corpl drs lnglni~rl drs Min'l Edmund Weiss, vol.5 (I 839-1855), Vienna (ou Ruudl d·OburvationJ J,fltlorologiqurs ~t 1866. An explanatory Foreword gives some Magnltiqurs) foitrs dans l'Itmdu~ tk l'Empi" tk details of the instrumen ts and their exposure, RUlli? published by order of his Majesty the height of the station, the original units Emperor Nicolas I (A.-T. Kupffer, Director of employed, corrections applied, and a few special the Observatories), St. Petersburg (Imperial observations on particular dates. Copy obtained Academy of Sciences), the 1845 and 1846 from the UK Meteorological Office Library, observations published, each in a separate volume, in 1848 and 1849 respectively. Brackndl. Obtained from the UK Meteorological Office Libraty, Brackndl. Ekaterinburg (now Sverdlovsk), 56°48'N, SWITZERLAND 600 38'E. Details as for St. Petersburg, in the BasIc (Menan), near 47.6"N, 7.6°E. Five times same volumes. daily observations of barometric pressure (in Paris inches and lines), temperature (in OR), lilli. (Tblisi), 41°4I'N, 44°57'E. Details as for wind direction and force (0-5 scale), and St. Petersburg. in the same volumes. abbreviated notes of sky cover and weather (h = heiter/clear, bw or bew = bewolkt/cloudy or Nicolaefsk sur la Mer Noire (Nikolaev), c. overcast, bed = bedeckt/overcast, R = Regen/ 47"N, 31.8°E. Three times daily observations of rain, Neb = Nebel/fog). Kindly supplied by the barometric pressure (printed in Paris lines) and temperatures (apparently in 0C), printed in Swiss Meteorological Institute (Schweizerische Suppllmmtl to the series of volumes in which Meteorologische Anstalt), Zurich. the St. Petersburg, Ekaterinburg, and liflis observations appear. No details of wind or Geneva, near 46.2"N, 6.1°E. Four times daily weather are given. observations of barometric pressure (reduced to O°C) in millimetres, temperature (OC), relative humidity (by hair hygrometer), and daily values AUSTRIA of maximum and minimum temperature and Vienna, near 48.2"N, 16.2°E. Three times daily measured rainfall (in m), also wind direction 61 Appendix twice daily and state of the sky and weather Paris, 48°52'N, 2°30'E. Four times daily (using extreme abbreviations, e.g. ·cou.pl" = observations of barometric pressure in couvert. pluid ovefCast, rain), in a printed millimctre's, and tempecature °C, at the tabulation, kindly supplied by the Observatory, Observatory, together with the day's highest and Geneva, under an arrangement made by the lowest temperatures and daily observations of Schweizerische Metcorologische Anstalt, the wind direction, weather and sky cover at Zurich. midday, kindly supplied by the Meteorologic Nationale (as for Rouen) from the· Compte. Rendus· of the Academy of Scienas. Monthly rainfall totals arc also given. FRANCE Montdidier, near 49.7°N, 2.5°E. A record of Dijon, near 47.3DN 5.1 0E. Details as for Paris, daily observations of barometric pressure (in except that daily rainfall measurements (in Paris inches and lines), temperature (°0, wind millimetres) arc also given. direction, and state of the sky and weather, extending from about 1780 to 1860; copy Rodez, 440Z I'N, 2°4I'E. A high-level station available on microfilm in the Climatic Research (630m above sea level) in the south of France. Unit, Universiry of East Anglia. Four times daily observations of barometric pressure (in mm ), and temperature (OC), Rouen, ncar 49.4°N, l.1°E. Three times daily together with the day's highest and lowest observations of baromeuic pressure in values, and once daily wind direction and state millimetres, and temperature in °C, as well as of the sky and weather at noon. Monthly the daily maximum and minimum rainfall totals also given. The relevant pages temper,uules, and once daily observations at from the ·Comp'es Rendus· of the Academy of noon of wind direction and the state of the sky Sciences kindly supplied by the Me,eorologie and weather. Rainfall totals for each month arc Nationale, as for Rouen. also given. An introductory text gives some details of the inSlruments and their exposure. The relevant pages from the printed observation collection, from the· Compus Rtndus d. i"Acadim/. ,us Sdmw·, Paris, kindly supplied SPAIN for this study by the Meteorologic Nationale Barcelona, near 4l.3°N, 2.ZOE. Three times (Service Meteorologique Metropolitaine, daily observations of barometric pressure: in Division de Climatologie). Ministere des Spanish inches and lines, and temperatures in Transports, 2 Avenue Rapp, Paris. OR, together with wind direction and a brief note of the state of weather and sky (in Spanish). Kindly supplied by Professor Manuel Mett, near 49.1 oN, 6.2°E. Details similar to Puigcerver, Secretary of the Academy of Rouen. The record for 1845 and 1846 kindly Sciences and Arts, Barcelona, from the supplied by M. Claude Pichard of newspaper Diario de Barcelona. (Reports of Gcispolsheim, Lorraine. from an archive in weather in this newspaper begin in 1792, but Strasbourg. the year 1845 seems to be missing). 62 Appendix GIBRALTAR Near 36.1°N, 5.3 W. Once days with wind, copied from printed summaries daily reports of barometric pressure (in English of the observations at Palermo in • Rist"tto inches), temperature (inOF), measured rainfall gmmzlr tklk OSJrrvazioni mfttorologicht fottt ntl (in inches), wind direction, and state of the Rtalt Omrvatorio di Paltrmo", in the British weather and sky, photocopy supplied by the (Museum) Library under Pressmark AC4122. kind arrangements made for this study by (The observations are believed to have been W.D.Hyde, Principal Meteorological Officer, made in the Alameda Gardens, 33.5 metres Royal Air Force, Gibraltar in 1982 from the (102 feet) above sea level: they are known to files of the newspaper Gibraltar Chronicle in have started in 1792 and the early years are the Garrison Library. believed to have been published by C.L von Littrow and F. Schaub in 'Storia celeste del Real Osservatorio di Palermo dal 1792 al 1813" SICILY (observations by Piazzi) in the Annalm dtr Palenno, near 38.1"N, 13.3°E. Monthly values Kaiu,.-KOniglicht Sttrnwarft.(NtUt Fofgt} &nd of mean barometric pressure (in English 4-12, 1821, under Press mark 8564 band c in inches), together with the highest and lowest the British Library. Some later years' data values measured during the month and dates of appeared in the Giornale astronomico e occurrence, similar details of temperature meteorologico del Osservatorio di Palermo, (in°F), rainfall and notes of the days with rain Palermo, 1855-1857; in the library of the Royal (and snow) falling, days of thunderstorms, and Astronomical Society. London. 63 Index Airmass analysis. 8 Disease of powees. 14 Air temperature anomalies. 17.21-29 Diaries. 13-16.32 Amerio. 4-5. 43. 47. 49 Analysis of weather map. 17-19 Effective blight hours. 8. 37-39 Anemometer, 15 Effective period. 7 Anticyclones. 20 England. 7-16 and p=im Atmospheric humidity. 7. 25 Epidemic. blight. 7. 34 -fungal ouse. 7 Barometric pressure. 16-18. 24 Europe. 3-4.13-14.25.35.42.44 Beaufort sale (force). 16 Beaumont period. 7 Faeroe Islands. 54 Belgium. 27.36-38.45.59 Fahrenheit scale. 15 and p=im Blight. earliest in England. 11 Farmers' Journal. Irish. 31. 36. 43 -hislOry of. 1.3-5.31 Farmers' Magazine. 34 -impact of. 35-40. 44-48 Finland. 55 -foliage. 5 Flanders. 34. 49 -fungus. 4 Foliar blight. 5 -infected area in 1845.34 Foliar deoy. 31 -losses caused by. 39 Force. Beaufort scale. 16 -palato,2 Foot-and-Moum disease. 11 -records, 9 France. 10. 14.25.28.32.42.62 -spores. 6 Fronts, weather, 9 -tuber. 6. 44 Fungicides. 7 -variety susceptibility. 36 Fungus. 8 Blight damage. 5. 46 Gales. 43 Blight. and weather. 7 Gardeners' Chronicle. 10.31.35.45 --- 64 Index Little ice age. 19 Reaumur temperature scale. 15 and passim Lumper potato. 36. 45. 50 Relative humidity. 7-8. 25 Russia. 13.42.61 Meteorological -analysis. 17-30 Sandanavia.49 - condidons for blight. 7-8 Scorl.nd. 25. 45. 49. 57 -- 65 Casde Fogarty. Thurles. 15th July. 1847 My dear Sir I did not intend writing to you until to-morrow. the 16th. the anniversary of the day on whim the first symptoms of the disease appeared on the potato stalks in this neighbourhood last year. and was certain of being able to give you a favourable report. but judge of my surprise when on coming home this evening after a day's tour through the country in company with Mr. Labam the Government Inspector to find large specimens of the fatal disease from two different parts of the country. one from Corrnackstown and the other from Drumeenaghlugh. left here for me. I examined them and found them to compare exactly with last year's first symptoms in every way but that the spots this year are not so black or inky as last (l enclose a sample). I went over my own this evening and upon close examination found many a bulb (?) infected. I have only one consolation or hope now left and that is there are 4 stalks of mine that were similarly affected on the morning of the lOth June. all but the epidermis. and have quite recovered the shock and are now quite healthy. A week will tdl mum. I have heard many other bad accounts this evening but will state nothing but what comes under my own eye. If the potato goes this year. Ireland will nrvn" nnon" reeD,,". I had sold meadowing to the amount of £200 this time last year but I have not yet had a single application for a plot. I must keep on cutting. The weather for the 4 days past was good and I tramped 19 cocks (in all now 28). It is now raining again. Hoping to be able to give you a good account still on this day or to morrow week. I remaIn. my dear Sir. Most respecdUlly. Your ob. humble sert .• JOHN MOLLOY James Lc:nigan. Esq .• (see page 12 for original letter)