The River Thames. 67

March 27, 1877. GEORGEROBERT STEPHENSON, President, in the Chair. No. 1,495.--“ The River Thames.” By JOHNBALDRY REDMAN, M. Inst. C.E.I IT is not even known who constructed the embankments which now regulate the stream in thelower reaches. No one can do more than speculate as to what was the condition of the sand-banks of the estuary before these embankments were raised. The tides must have had free range orer the large areas of the Essex and Kent marshes, now, ordinarily, near the river, 7 feet below the level of highwater of aspring tide; and Wren, ia hisParentalia,” philosophised as to the early conditionof London. Theabstraction of tidalwater on eitherbank for 30 miles inlength and for an averagewidth of only fr mile on either side, by 3 feet in mean depth, would represent nearly 70,000,000 tons. The areas of the Essex and Kentish marshes on the river banks a.n?ount to about 30 square miles; and assuming 3 feet as the average tidal depth, the abo5-e is the quantity of water shut out ; if the average depth were 7 feet the amount excluded would be more than double. Thetotal quantity of tidalwater betweenTeddington and Sheerness may be thus stated :- iym- width. Mean- range. Miles. Feet. Feet. Tons. London Bridge to Sheerness . 43 X 1,500 X 15 = 142,533,482 LondonBridge to Teddlngton. 20 X 500 X 10 = 14,732,143 Grave=d to Sheerness, extra 16 4,000 15 = 141,428,571 width ...... l As the last quantity but sliglitly affects the consideration, and as the outline of the river was little altered by these early works, the quantity of tidal water acting upon the river above Gravesend may be assumed to have been reduced proportionately by these

1 The discussion upon this Paper occupied portions of three evenings, but an abstract of the whole is given consecutively. F2 Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. 68 MINUTES OF PROCEEDINGS. early embankments. Now, on the supposition that high-water level was raised 12 inches, they would return as an equivalent-

Tons. 50 X 1,200 X 1 = 8,839,285 In effect about one-eighth of the volume abstracted. They must, however, have returned a much larger proportion as an equivalent by the deepening of the low-water channel. If the comparison be limited to Gravesend, whichis perhapsmore correct, it would stand thus :- Man- width. Mea11- range. Miles. Feet. Feet. Tons. LondonBridge to Gravesend , 28 X 1 ,500 X 15 = 92,812,500 London Bridge to Teddington,as before . . . . = 14,732,143 Totaltidal column ...... = 107,544,643

Thus the quantity of water shut out by the embankments may be equal to from five-eighths to three-fourths of the present tidal column, while one-eighth of the quantity abstracted is returned by raising high water. As regards the low-water equivalent, it is impossible to hazard a conjecture of the quantity. Looking at the great depths in the several reaches, the existing course of the river was undoubtedly the low-water channel before the commencement of the embankments,whether by the Romans or the Saxons, andthe great conservative agent was then, asnow, the tidal wave.

UPPERREACHES. The treatment of the upper reaches of the Thamesis involved in as much obscurity as the lower reaches and estuary. So far back as history extends, the Church appears to have had the monopoly of the fisheries;monks were the residents of the fair slopes of Windsor, and it was from the Church that theCrown obtained the site, since the favourite suburban residence of our monarchs. The establishment of the first locks, weirs, andtheir natural adjunct the mill is in most cases unrecorded; but their names indicate their origin, and the Churchman and Crusader went hand in hand in establishing and profiting by these useful and necessary adjuncts to agriculture. The Temple Mills above Bisham and Marlow, and the Temple Mills on the river Lee, situate at theverge of the tide, had a common origin; they were both founded at the same period by thesame semi-clerical and military fraternity; both were origin-

ally corn mills, subsequently copper mills ; one afterwards became a paper mill, and the other has now lapsed into desuetude and un- productiveness, and is only commemorative of a regime long passed away. The Abbey Corn Mills at Chertsey, again, show their origin in their name, and the same remark applies to those on the Channel- sea, Abbey, and Mill streams, north-east of London, tributaries of the riverLee, itself a tributary of the Thames.

OLDLONDON BRIDGE. Whilst the Church in earlytimes was the great architect of the age, as well as mill-owner, so also it was the civil engineer of the period. The first bridge across the Thames had for its author Peter of Colechurch, a monk, to supply accommodation to the numerous pilgrims passing from Southwark to London. Its history is well known, and for centuries it was the only means of communication from the south to the north side of what is now the metropolitan area, but was then the siteof several towns, London, Westminster, Southwark, Lambeth, &C.,all situate in open country, the twolast under the name of Alsatia, the refuge of the outlaw, and preserving even to the present day its peculiar identity. The fact of London Bridge having been for six hundred years the only means of communication north and south has had a wonderful influence in the resultant conformation of the metropolis and the arterialmeans of intercourse ; all themain roads north and south converging towards the bridge.

POWERSOF KIVER. As a natural means of intercourse, and as a sanitary agent, the powers and resources of theriver have been overtasked to the utmost. It has been treatedin the most fickle and capricious manner, and made an instrument to fulfil the selfish purposes of those resident on its banks. At an earlier period it might, by a general and more comprehensive view, have been made subsidiary to the benefit of the country at large. Various as arethe duties devolving on theriver, being the main drain of the metropolis, supplying potable water, tidal oscillation, and, above all, being the carrier of its colossal commerce ; no less numerous are theconflicting interests whichbenefit thereby. The origin of the early locks is obscure; most of them were formed for isolated purposes, andthe constant disputes,even now, between those possessed of abbeyfishing rightsand the general community are only indicative of this spirit.

CONMONS’REPORT, 1799. Thereport of the House of Commons of 1799 on therivers Isis and Thames is perhaps the first public document giving a general view of the then condition of the river. At that time, notwithstanding locks and weirs, those rivers and their tributaries had arrived at such a condition as to demand legislative measures for their conservation. Numerous schemes were proposed for getting over the difficulty, not by the erection of new dams or weirsand locks, butby abandoning the neglected stream alto- gether, and making the river the feeder of an artificial river or canal, to shorten the journey andrender more easy the navigation. Such was Brindley’s scheme for a canal from Monkey Island to Boulter’s Lock, happily never carried out.

OLDLONDON BRIDGE.-REMOVAL AND RESULTS. The great result of the inquiry of 1799 was, subsequent to the formation of the large centralarch, the entireremoval and rebuild- ing of London Bridge; the attendant results of which were thc failure of the foundations of Mylne’s bridge at Blackfriars in1836 ; the subsequent partial reconstruction andunderpinning of thc latter bridge, and the quickly following failure of Labelye’s old Westminster Bridge (always faulty), and similar treatment. Both were attacked by the same inveterate symptoms after their appa- rent renovation. At Blackfriars, ten years after the repairs, the river bed was 6 feet lower; and a similar cause produced a like result at Westminster. At the latter site, Page’s elegant structure is supported upon piles and caissons carried down int,o the blue clay so great a depth as to promise it a fair lease ; whilst at Blackfriars the late Mr. Joseph Cubitt, Vice-President Inst. C.E., sank wrought-iron caissons to so great a distance into the same formation as to insurea similar long life ; but there is no blinking the fact, that hitherto on the Thames, as on the Tiber and Clyde, bridgeengineering has been antagonistic to river conservancy, and even now the two are in direct antagonism,notoriously exem- plified by the condition of the foundations of Waterloo Bridge on the Lambet,h shore, with their series of broken Kentish rag stone outwork slopes upon a mud foreshore. It waa designed by Rennie before the removal of old London Bridge, and to the then contour of the bed and low-water regime of the river, the present enormously altered condit,ion of which, especially in theupper reaches, is theresultant of numerous

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. THE RIVER THAMES. 71 causes. That the removal of old London Bridge was not the sole one is evidenced by the continued and progressive lowering of the river bed and of the low-water level ; it was the main cause, but it was followed subsequently by numerous other active agents- the removal of old Westminster and Blackfriars bridges being the chief-the attendant results to navigation area progressive lowering of the river bed. Bdded to this the systematicremoval of the natural half-tide weirs, which kept back the ebb in the shape of shoals, such as the largehalf-tide island off Montagu House, below Westminster Bridge,which made its appearance at low water thirty years ago ; and mch patches as the Blackwall rocks and Daggenham shoal, which had on them only half the normal depth of the surrounding river at low water, have had an extraordinary effect, not only in developing the flood, but in accelerating the ebb ; and although in cubic quantity 25 per cent. may be added due to the removal of old London Bridge, it is an open question whether this amount is not to be increased one-half, i.e. by 12 per cent., or 37 per cent. in all, due to theremoval of all those obstructions by the tide and the steam dredger. The result is an earlier and a longer flood, with increased altitude, and a shorter, lower, and therefore greater scouring agent on the ebb.

EARLYTIDAL COSDITION. Five centuries back the time of high water at London Bridge was reckoned three hours aft,er the moon’a transit ; now it is two hours after, having been accelerated one hour. In the year 1700 the flood tide commenced three hours fifty minutes before high water; it is now five hours and a quarter, nearly one hour and a half earlier. In 1830 high water at London Bridge was one hour .and three-quartersafter Sheerness, now it is one hourand a quarter, a gain of thirty minutes in farty-sixyears, due mainly to the removal of old London Bridge, the sectional area of whose water-way was 7,300 superficial feet, as compared with 17,600 feet, the area with the present structure. The old bridge, due to its massive piers and projecting “starlings,” acted as a partial weir. The spring tides rose 6 inches higher on the lower than on the upper side, resulting in a step down of the high-water level from time not being allowed for it to attain the same altitude above aa below the bridge; and at low water there was a step downwards, .and a greater hindrance to the ebb due to the starlings ” formed of a nest of piles projecting beyond the piers, and a fall of from 3 to 5 feet of water was the result.

PRESENT TIDALCONDITION. By the removal of the old bridges, and by the substitution of modern structures with ample spans, the tide now flows higher by 12 inches above bridge than in former years, and ebbs about 4 feet lower abovebridge, adding in effect about 25 per cent. to thetidal volume of waterpassing up and down twice in the day, and producing a rapid lowering of the bed, and greater exposure of the mud foreshores, the worst of which have been reclaimed and covered bythe Thames Embankments. The low water has been lowered all the way from London Bridge to Ted- dington, viz., 4 feet at London Bridge, 3 feet 6 inches at West- minster, 2 feet 6 inches at Battersea, and about 2 feet at Tedding- ton. The level of high water below bridge is much the same a6. formerly, but the increase in altitude is equal to 1 foot at Batter- sea, which, added to the depression at low water there, gives an increased range of 3 feet 6 inches. The ebb current has also been increased, and the water ebbing downwards over Teddington weir now passes through a smaller channel. The result is a lowering of the bed. Thetidal water between London Bridgeand Ted- dington having been thus increased by about one-f0urt.h part, and! added to thatbelow bridge, has produced a corresponding progres- siveimprovement of theport of London, aided bysystematic dredging of shoals. This is further requiredbetween London Bridge and Teddington; also in places below bridge. The velocity of the firstof the flood above bridge is from 12 mile to 2 miles per hour, and of thelast of the ebb from 2% to 3; miles per hour. At the mouth of the Thames, south of the Maplin Sands, the greatest rate of springs is 23 knots per hour, at the Kentish Enock 2.8, and at the Sunk 3 knots per hour ; the two last being off the mouth of thc river. The interest attached to the well-being of the river, the great. artery of British commerce, has been evinced by numerous plans. discussed during the last half-century ; works that will regulate the breadth, increase the scour and depth, promote an increased rangeand duration of tide, areassisting nature’s greatagent,. which, in its ever-recurring regularityof action, may be regarded as an emblem of the Infinite, and has, in its ceaseless pulsations, well given rise to theold adage “Time and tide waitfor no man.” Pliny’s comparison of the progress of a river to the life of man is well known and oft quoted, and Denham’s lines on the Thames contain a similar thought. It has been noticed as a characteristic of the river that, at the original formation of shiresand sub-

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. THE RIVER THAMES. 73 division of land, it was a noted stream, and that from Cricklade to Sheerness it is the natural boundary of counties. Rennie’s Report of 1834 referred to itsinsignificance as compared with its diffusion of wealth, power, and activity over the whole earth, making it incomparable to all other riverscombined; to its drainage area of 5,162 square miles; its length, with windings, 2015 miles, about double the direct length; its reception of twenty tributaries-fifteen of the principal are given in the FisheriesCom- missioners’ mapwhose united length amounts to464 miles ; the fall in its navigable length from Lechlade to London of 258 feet, or about 21 inches per mile ; its mean velocity 2 miles per hour, and the quantity of water flowing over Teddington weir at that time as 1,337 cubic feet per second.

,DRAINAGEAREA.-TABLE 1. The importance of the drainage area of the Thames when compared with the other riversof England is illustrated by Table1.

LONDOKWATER SUPPLY. A volume of 1,337 cubicfeet per second wouldbe equal to 3,22,3,125 tons of water daily. The present daily quantity sup- plied to the London water companies appears from Major Bolton’s lastreport to be 121,622,500 gallons, or 542,958 tons, so that nearly one-sixth of the total quantityof land water is abstracted for the London water supply. This is equal to 198,179,670 tons of water as the annual want of London; now, however, sometimes estimated to include all demands at 250,000,000 tons. The annual outflow of the Thames. is 1,176,440,625 tons, which is equivalent to 3+ inches of rainfall over the drainage area of 5,162 square miles. Taking the annual rainfall at 24 inches, the London basin would yield 8,030,597,142 tons of water. Taking one-fourth of this amount, after allowing forevaporation, &C., 2,007,649,285 tons of waterare available. This estimate is, however, about one and two-thirds the actual result, or in other words, instead of a depth of 6 inches of annual rainfall beingavailable, not much more than one-half, or 3fr inches, is so, and this is only four times the quantitynow required for the metropolitan water supply. The average outflow is equal to from one-sixth to one-seventh of the annualrainfall. The Royal Commissioners of 1869 estimated theamount at double, and that estimate appears excessive, the loss from evapo- ration,absorption, &C., accordingto Mr. Greaves, M. Inst. C.E.,

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. ‘74 NINUTES OF PROCEEDINGS. amountingto 20h inchesout of the 24 inches annualrainfall. TheWater Supply Commissioners of 1869 only dealtwith the drainage of theThames valley above Kingston,amounting to 3,676 square miles, or less than three-fourths of the entire area. They estimated theaverage annual rainfall at 27a inches, and that one-third flowed down at Hampton. The total quantity would amountto 6,493,227,321 tons; one- third of this amount is equal to 2,164,409,107 tons. This again is nearly double the actual outcome, showing that insteadof 9 inches depth of rain being available, the amount is not inore than 4$ inchesover this contractedarea. It resultsthat Londonnow requires a quarter of the actual outflow of the Tbames for water mpp1-f. NAME. The liverfrom Thames Head, nearCirencester, in GloucestersSlire, has been rather capriciously named the Isis, until its junction with the Thame, 15 miles below Oxford.

LEVELOF HIGHWATER. The relative levelat high water at Sheerness and London Bridge was fixed by Mr. Lloyd,’ byspirit-levelling for theAdmiralty in 1830. He deduced that at that time the tide attaineda greater -altitude by 2 feet at London Bridge; from a comparison of the ,oscillations of thetidal column at thetwo places, there is 8 greater range by from 4 to 5 feet at London Bridge, where the tide now ebbs at times from 12 inches to 2 feetlower than at Sheerness, due to the fact that the tide is still ebbing in the Pool whenthe flood is making at Sheerness, and continues to do SO -untilmet by the flood. Illustrative of this action, it is only necessary to point to Glasgow, where the spring tide rises as high at Greenock, and ebbs 6 inches lower ; and to the Tyne, where similarresults occur. These cases might be multiplied by ex- amples around our coasts.

MR. ROBIXSOX’SPAPER. Reference may be here made to a Paper “On thePast and Present Condition of the RiverThames,” read before the Institution by Mr. Henry Robinson, Assoc. Inst. C.E., on the 22nd of February, 3856.’ Mr. Robinson referred to Caesar’s description of the river

..- ~~~ . __ ~ - ’ Sometimes called Lieutenant-Colonel John Augustus Lloyd, he having been ;a Captain of Engineers in the Columbianservice in 1827, Then he levelled ?between the Atlantic and Pacific Oceans. Vide Minutes of Proceedings Inst. C.E., vol. XV., p. 195.

as “ Alma ” in his Commentaries ; to the reference to its locks, &C., in Domesday Book; to the stipulations in Magna Charta for the removal of all weirs and obstructions, and subsequent edicts ; that Quem Elizabeth directed special attention to its conservancy ; the early condition of the estuary; the ancientname of the metropolis, “ Llyn Din,” or town on the lake ; the difficulty of navigating the reaches above tidal influence ; the practice of flashing at the weirs; the obstruction caused bywater-mills atthe locks ; thelarge amount of tonnage-265,000 tons at the close of the last century, now mainly absorbed by the railways ; the Acts of James I. not acted on; that of George 111. appointing commissioners for six districts into which the river was divided; the vast number of commissioners and unwieldy character of the body ; the fact that at that time restriction upon making any lock below Maidenhead existed ; the canal schemes of Brindley’s time ; to Rennie’s report of 1794; and to Mr. Vanderstegen’s successful crusade against the canal schemes, resulting in powers being given, in 1810, 1812, and 1814, to theCorporation of London to erect locks where required,and tothe sixpound locks erected by the lateMr. Leach between Penton Hook and Teddington, a distance of 15 miles, by which 21 feet out of 32.feet fall of water were penned up, all but the first having weirs with paddles removable in floods; and to the irregularities in the widthsof the tidal reaches below, and the various embankment schemes to remedy this from the time of Trench, Martin, and Walker, to the present time.

LONDONERIDGE.

The first was built between A.D. 993 and 1016, in the time of Ethelred. This bridge was destroyed in 1136 by fire, and repaired, but in 1163 was in so ruinous acondition that Peter ofCole- church commenced the stone bridge, which was completed in 1209 underthree citizens, notwithstandingRing John’s recommen- dation of one Isenbert, when Peter of Colechurch died or became infirm. In 1280 the bridge became ruinous, andtolls for its support were authorized inthe time of Edward I. In 1426 thedraw- bridgeand tower for defence were erected;in 1582 thewater- works were constructed ; and after numerous fires, the great one of 1666 destroyed all the houses on the bridge, but they were again yebuilt. In 1757-58 the houses were removed, a temporary bridge being built for the operation, and the large arches were formed subsequently.

TRADE OF LOXDONAND MODERN TTORKS.-TABLE8. The trade of the Port of London could never have been quad- rupled in a century, from 1700 to 1800, quintupled in the SUC- ceeding half-century, and continued to increase in a greater ratio up to .the present time, but for works regulating the channel and promoting and developing the tidal flow. To say that the river improvements cannotbe greatly extended would be totake a narrow view of the subject ; the dredging engine is the requisite agent, and doubtless the tide will maintaina much deeper channel than the minimum water hitherto existing over the shoals. This work is beingactively prosecuted bythe present Conservancy Board. Prior to their appointment, from the fact that only such material as was saleable, viz., gravel, was dredged, a large arrear of work fell to the presentauthorities.

DELTA. The variations of the sand-banks are constant. They are carefully buoyed and watched by theCorporation of the TrinityHouse ; the main channels marked by floating and fixed lights ; and in addition, the lower reaches have been lighted of late years, where the half-tide foreshores, gradually increasing in width, obtain their maximum, viz., 5 miles, at low wateracross the Foulness or Maplin Sands of the Essex shores. To show the fluctuating character of the sands of the estuary, reference may be made to the modern buoyage of the “ Prince’s Channel,” on the south side, which is now the main channel for outward-bound vessels, having super- seded to a great extent the use of the “ Queen’s Channel,” ko the south of it, which has 6 feet to 12 feet less water ; also to the recent formation of a deep channel between theGirdler and Shingle Sands. Andthe Girdler Channel has been supplantedby a channel more tothe north-east, between theWest Girdler ancl Shingles, called theShingle Channel upto the arrival of the Princess of Wales, who passed through it, and it has since borne the name of the Alexandra Channel. Also to the recent breaking through of Bullock’s Channel, between the East Girdler and Long Sands, thus increasing its depth into the “ Black Deeps ” from 20 to 40 feet.

LOWERXEACHES.-LOW-TVATER DEPTHS. The maximum low-water depths in the estuary givea good idea of the volume of water in the lower channels. In Sea Reach there

is a depth of 60 feet ; below the Nore, 66 feet, and a similar depth in the Medway ; but north of the dockyard the outfall hascreated a maximum low-water depth of 100 feet, shoaling again in an east- north-east direction to 19 feet. Between the Maplin and Mouse Sands there is a depth of 72 feet, and in the neighbouringchannels of 66 to 78 feet; in the Prince’s Channel of 72 feet, and in the Queen’s of 60 feet generally, and in the Hole ” of 105 feet.

UPPERREACHES. Upwards, the water attains a depth of 55 feet above the Kore, 30 feet in Leigh Road, 48 feet south of Chapman Sand, 61 feet off Holy Haven, 61 feet in Sea Reach, 30 feet off the Lower Hope, 33 feet off the Mucking, 53 feet in the narrow part of the Hope, 49 feet off Coalhouse Point, 56 feet in Gravesend Reach, the same in Northffeet Hope, 52 feet off Grays, 44 feet in Fiddler’s Reach, 43 feet off Greenhithe, 40 feet in LongReach, 25 feet in the Rands, 34 feet off Erith, 30 feet in ErithReach, 25 feet off Rainham Creek, 22 feet in Half-way Reach, 21 feet in Barking Reach, and 19 to 21 feet in the Gallions. The navigable depths are usually lower from shoals; but the above enumeration indicates that the minimum low-water channel may be much developed. The upper reaches to Woolwich have a general low-water channel of 20 to 15 feet deep; and upwards to London Bridge of 10 feet.

+ METROPOLITANREACHES AND EMBANKMENTS. The condition of the metropolitan reaches had been but little improved notwithstanding the multitude of suggestionsto ame- liorate a state of thingswhich became, from thenumber of questionsinvolved, more and more difficult todeal with each succeeding year. The first comprehensive plan was thatby Sir Christopher Wren, after the fire of London in 1666. In 1767 an embankment was carried out by Mylne on the Middlesex shore in conjunction with Blackfriars Bridge. The well-known terrace of Somerset House by Sir William Chambers, the AdelphiTerrace and embankment in1770 by the brothersAdam, and the Millbank embankment, in1830, complete the listof such works above bridge, until the formation of the embankment in front of the Houses of Parliament. To these may be added the commercial quays on each bank below London Bridgeand at the docks, the Greenwich Hospital and Pier embankments, Cubitt’s embankment of the Isle . of Dogs, andthe quays at Deptford and Woolwich Dockyards.

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. 7s MINUTES OF PROCEEDINGS. Beyond these but little had been done in the way of any comprehensive embankment measure until the agitation of the question byTrench and Martin, the laying down of linesby Walker, Bullock, and Leach, and the partialcompletion of the work by Sir Joseph William Bazalgette, M. Inst. C.E., who has also nearly completed the other greatwork of the day, thediversion of the drainage of London to thelower reaches of the river atDagenham and Plum- stead. It is the fashion with Englishmen tosneer at works at home. Nuch was said of the Seine when the Thames Embankments were first projected. It is suggested that the Thames Embankment is the greatest metropolitanimprovement of modern times, and is unrivalled in any city of Europe. Certainly the resultant effect, whether viewed from the river or the bridges, is finer than had been foreseen by any of its early and most sanguine promoters, except perhapsin the characteristic sketches by . thepainter Martin. To show the neglectof the river prior to theseimprovements reference may again be made to the Commons’ report of 1793, the Committee directing particular attention to thefact, that with the exception of various Acts for the improvement of the river, and numerous schemes with the same object, no regular survey or plan of the river had ever been made, nor had anysystematic scheme of improvement been acted on.

SEWAGE. Before the diversion of the metropolitan sewage another altered condition of the river had been entailed; for what under the old statutes of sewers was illegal, became, consequent on the introduc- tion of a more plentiful water supply and modern appliances, gradually legalised, viz., the connection of house drainage with the sewers, originally laid outonly to carry off the rainfall of the valley, termed by Callis in his well-known work “a fresh water trench compassed in on both sides with a bank, and is a small cur- rentor little river.” The work of Roger Griffiths, theWater Bailiff, of 1746, dilates on “ the Beauty andValue which the River of Thames is to the Publick.” He refers to the extent of its navigation and shipping, the nursery it forms for seamen, and ‘(the invaluable blessing we have in its Fishery,” and says lovingly, “ it far exceeds all other rivers in the known world. Should not,” he appealingly adds, “ such a’ River be therefore carefully preserved from all Obstacles and Damages thatmay occur eitherto its Navigation or Fishery?”

THETIDES. Unusual ranges of tide due to gales, and the double tide from similar causes, naturally attracted attention from an early period, whenthe low-lying parts of London weresubject to floods. Holinshead and Stow described them, and in Gongh's Topography a paper was published describing a double tide, which occurred on Friday,the 4th of February, 1641. Theriver banks were overflowed in 1099 ; in 1114 the tide ebbed so low that persons walked on either side, and under London Bridge; the same cir- cumstance is recorded in 1158; on the 10th of February, 1238, Westminster Palace was flooded ; in 1242 the banks were burst, andthe country under water for 6 miles;in 1270 thisagain took place ; Stow records that Westminster Hall was flooded on the 30th of September, 1555 ; on the 26th and 27th of January, 1564, there were double tides; on the 6th of Xovember, 1574, a. high tide burst the banks, and a reflux after an hour's ebb occurred; in 1607 and 1641 double tides occurred; and in the first year the river was frozen over. Pepys mentions that of the 7th of December, 1663, thus :-" I hearthere was the last night the greatest tide that ever was. remembered in England to have been in this river : all Whitehall having been drowned." Taking the levels of the lowest parts of Whitehall, this height was possibly from 3 to 4 feet above Trinity standard. On the 13th of December, 1717, the tide ebbed so low, with a violent westerly wind, that persons again walked across, and under London Bridge. On the 31st of December, 1732, a hightide overflowed Wapping, Tooley Street, &C.; on the 9th of February, 1762, the banks were overflowed; on the 10th of March, in the same year, the tide flowed into Westminster Hall ; on the 13th of February, 1763, this again occurred, covering the floor to the depth of 4 feet (this would be3 feet 2 inches above Trinity standard) ; and on the 18th of November of that year there was a double tide. On the 28th of September, 1764, the marshes were again overflowed and cellars filled; on the loth of April, 1768, the 'I sand banks," described as existing on each side of London Bridge, are said tohave been dry. On the 2nd of February, 1794, a high flood tide Overflowed both banks above Westminster Bridge ; in Palace Yard it was 2 feet deep :-" Boats came through the passage of Old Palace Yard from the Thames and round upto Westminster Hall gate. Thetwo ScotlandYards, Privy Gardens, Whitehall, were under water, and many parts rendered

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. SO MINUTES OF PROCEEDINGS. impassable for two hours. Westminster Hall suffered much ; the water ran in at the greatdoor for upwards of an hour, and wasup to the second stair leading to the Court of Eing’s Bench.” This would appear to have been from 2 to 3 feet above Trinity standard. Thedevastation caused bythe above tides was due, no doubt, to the bursting or overtopping of earth banks before wharves had become general. FORESHOREBEACHES. There is curious evidence Erom these old records that there was a riverbeach, as it were, on either side of old London Bridge, where the tide was checked ; and a similar thing is observed at the presentday. The Author has frequently walked along and noticed the variation in, the wasting away and re-accumulation of a beach of small pebbles in front of the terrace embankment of GreenwichHospital, lying in the deep *bight fronting the Isle QfDogs. He has also repeatedlynoticed the same thingwhilst engaged on dock and wharf works in the neighbourhood, at the head of the long reach on the western side of the Isle of Dogs, where a natural beach of small pebbles and sand forms on the top af the mud foreshore,as at Greenwich and along the Lambeth and Millbank shores.

GRAVESEJDTIDES.-TABLES 2, 3, AND 10, PLATE2. From a register kept by the Author at Gravesend from 1842 to 1845, he found the extreme range of tide to be 24 feet 6 inches. A high tide on the 18th of October, 1841, estimatedto be the highest on record for half a century, rose 1 foot higher than any l ,, Westminster. At-Blackwall on the- 12th December, 1845, it rose 3 feet 4 inches above Trinity standard. 24th January,24th 1850 ,, 3 ,, 4 ,, ,, ,, 12th November,1852 ,, 3 :, 7 ,, ,, >, 15th February, 1854 ,, 3 ,, 5 ,, ,, ,? 22nd December,22nd 1863 ,, 3 ,, 6 ,, ,, ,, 24th November, 1866 ,, 3 ,, i ,, ,, 1 1st March, 1863 7, 3 ,7 4 7, ’7 >7

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. THE RIVER THAMES. S1 The highestof these, that of November 1862, exceeds by 4 inches that of 1841, giving an extreme range of 25 feet 10 inches at Gravesend. Thetide of the20th March, 1874, was 9 incheshigher, or 4 feet 4inches above Trinitystandard, which increases the rangeto 26 feet 7 inches;and the highest tide of all, that of the 15th of November, 1875, was 4 feet9 inches above Trinity standard, making a total range of 27 feet. It may be noted thatthe two great tides of the15th of November, 1875, and of thO 2nd of January, 1877, occurred in each case the day aftera gale from the west, raising the Channelsea to an almost unprecedented height, and which would require three tides, or 20 hours, to complete the circuit of t,he English coast before its full effect would be felt in the riverThames.

TIDALIRREGULARITIEZL-TABLE 4.

Lord Anson in 1756 described, in the ‘I Philosophical Trans- actions,” the irregularities of the tides caused by a shift of wind and gales, duringand after which there is an extraordinary acceleration andsubsequent falling off of the tide. This was shown during the gales of October and November 1859. On the 26th of October there was a difference of 3 feet 10 inches between the morning and afternoon tides, and of 3 feet 8 inches between the afternoon tideand that of themorning of the 27th, and 3 feet 7 inchesbetween two succeeding tides in thegale of November. This difference of nearly 4 feetin the rise of two succeeding tides, and amounting in some cases to 6 feet, is exceptional, anddue to rapid change of windduring gales. The amount was 7 feet 5 inches on the 8th of January, 1839, and on the 21st of October, 1874. A comparison of thesevariations at Sheerness with London is confirmatory. In some cases they are almostidentical. Usually theyare less at Sheerness, andthe variation of the barometricalpressure is generally sympathetic, butnot always so. In most cases these great differences have occurred during,and more especially after,changing gales of wind, and it willbe observed by reference toTable 4, that 3 to 4 feet is the ordinary difference in level. In cases of extreme variation this may exceed 7 feet, or one-third of the total oscillation of spring tides.

SHEERNESSAXD LONDOXTIDAL RANGE. The existing greatdifference in the rangeof tide between Sheer- ness and London shows how much low mater has been lowered atthe latter. When Mr. Lloydtook levels, in 1830 lowwater was estimated byhim as 1 foot 8 inches higher. It now ebbs lower than at Sheerness, and the high water now ranges 3 feet 10 inches higher than at Sheerness. Captain Maughan, for many years Dock Master at the London Docks, determined byhis ttables thatthe maximum range of tide in thePool had considerably increased as the rise of springs.

Feet. Inches. In 1800, fixed by the Trinity Corporation, was . . 18 0 ,, 1843 it was ...... 19 G .. 1864 ,, ...... 20 P .. 1866 ...... 20 8 .. 1S74 and now ...... 22 0

EFFECTOF E~BANI~~~E~TS.-TABLES6 ASD 7, PLATES 2 AND 3. The future improvement and development of the resources of the river are dependenton works that will increase and not check the tidal range ; that will regulate the widths and depthsof the low-water channel,and generally encourage thetide upwards. Bespecting thc effect of theThames embankments as yet constructed on Walkey’s lines, there is,even among those having thebest opportunity of forming a judgment, a very diverse opinion. The Royal Commission gave a guarded opinion as to the results to be anticipated, and suggested that if detrimental, compensation reservoirs might be formed higher up the river, to storetidal water and return it on the ebb. Beservoirs of this type were constructed about sixty years back on the Channelsea river, a tributary of the Lee, with self-acting swivel pivot gates to the sluices, with one-half of the leaf farther from the centre (on theDutch plan) ; but they were seldom used, and were aban- cloned by the Lee Commissioners under their last Act. It must be obvious that the value of riparian land within the tidal range is so great as to render the construction of such reservoirs, which would have to be more than 50 acres in area, very costly; and thealternative is presented whether,if compensation be necessary (which is not, however, for a moment suggested), another method more conducive to the interest of the river might not bc adopted, viz., not the extension of lockage downwards for the local

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. THE RIVER THAMES. 83 benefit of towns on the verge of the tidal flow, but tidal extension upwards, by the removal of Teddington Lock, and dredging and regulating the stream above and below it. Has the abstraction of the 50 acres or thereabouts reclaimed by theThames Embankment, in front of Whitehall and the Adelphi, and along the Lambeth :shore and at Chelsea, covered at high water by a mean depth of ,G feet of water, representing about 365,000 tons passing downupon the early ebb, produced any sensible effect ? or has this been compensated for by the dredgingof shoals and thedeepening of the low- water channel below ? Or have the embankments compensated for this abstraction by raising the tidalcolumn and causing the high- water level to reach higher in the reaches above these works, and so produced an equivalent for the water formerly overflowing the reclaimed slobs ? Two opposite opinions are held on this subject. Some persons argue that not only does this abstraction of water deprive the river of a valuable tidal scour it formerly possessed, butthat the narrowing of thechannel by theseembankments absolutely stops ” the tide, and prevents it flowing so high up the country as formerly. On the other hand, it is asserted that the embankments compensate for any abstractionby a prolongation of -thetidal action upwardsand its consequent acceleration. Some persons in the first category even say, that an assumed falling-off .of the tide in the Fool; amounting to 7 inches, is attributable to the embankments. The first question that arises is, have the tides at high water fallen off in thePool ? Undoubtedly thelow water is considerably lower, but from tidal observations at thevarious docks it does not appear that there is any falling off at high water; and as regards the river above bridge within the in%uenceof the Embankments, the tides undoubtedly attain a higher range than formerly during equinoctial spring tides. The best possible proof that the tides have not fallen off in the Pool is a reference to Table 6, from which it will be seen that the average high water for the year 1875 was 13 inches below Trinity standard, and this is precisely ‘6 inches higherthan the average height as calculated inthe Admiraltyyearly tide-tables. From 1836 to 1842 theaverage height registered at the London Docks was 16 inches, or 3 inches lower than in 1875. The low water of 1873-75 was also 5 inches .lower than the mean low water from 1833 to 1843, and the mean range increased by 7 inches. That the Embankments can have little effect in stopping the tides, as some persons assume, is evident from the fact that the minimum width, 700 feet, and consequent maximum depth, viz., 02 Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. 84 MINUTES OF PROCEEDINGS. 15 feet at low water, existed prior to those works at the Millbank- PenitentiaryEmbankment, which had gauged the stream for thirty yearsprior to their erection. Thisminimum has been somewhat increased by the setting back of the Albert (Surrey). Embankment. To show that the Embankments are recuperative, and afford a compensation by raising the tidalcolumn in exchange. for what is abstracted, it may be stated that, assuming the surface at high waterfrom Blackfriars to Battersea is raised 6 inches for a length of 5 miles, with an average width of 1,000 feet, a corresponding equivalent would be afforded, viz., 368,000 tons. How- ever, 750 feet is more probably the average width, and this gives. 276,000 tons as compensation. Ifthis be estimated between Blackfriars and Teddington, a length of 19 miles, at an average width of 500 feet only, the amount is 700,000 tons, nearly. This approximates closely tothe estimate of Captain Maughan, for many years Dock Master at the London Docks. He estimated the areas under the Acts of 1862-63 authorized to be embanked m. follows :- SuperficiaI feet.

Ou the north shore from Westminster to Blackfriars . l ~ 645,457 From theHouses of Parliament toChelsea . . . . 502,520 Surrey shore below Westminster Bridge. . . . . 720,000

This area he assumed to be covered at high water of spring tides by 10 feetdepth of water,an extreme depth, and this yielded a tidal abstraction equal to 800,000 tons. This is small, although it is compensated for by the action of theEmbankments, con- sidering the enormous amount of additional tidaI water admitted by the removal of old London Bridge, thus,

Miles. Feet. Tons. 20 X 750 X 3, averageincreased range . . = 6,629,466 or- 20 X 500 X 3 ,, I, ,, . . = 4,420,000 In factthe latter and smaller amount is five tosix times the. quantity affected by the Embankments.

HIGHTIDE, 20TH OF MARCH,1874. The tide of the 20th of March, 1874, attained an altitude of 4 feet 4 inches above Trinity standard, 9 inches in excess of that in November 1852, which latter was aided by a land flood, and. thus higher than any previously recorded. This directed attention

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. THE RIVER THAMES. 85 to the general question of the river, and the completion of the Embankment and raising the wharves and banks in the lower reaches have been publicly discussed and entertained.

HIGH TIDE,15~~ OF NOVEMBER, 1876. This tide, the result of the great westerly gale of Sunday, 14th of November, aided by a heavy land flood, is the highest on record inthe Port of London, havingattained an altitude of 4 feet 9 inchesabove Trinity standard; but it was relativelyhigher, exceeding theAdmiralty calculated rangeby 3 feet 3 inches; whereas that of the 20th of March, 1874, was only 2 feet 2 inches above the Admiralty estimate. The lamentable results attendant on the periodical overflowing of the Thames in the low-lying and poorer districts of the metropolis cannot be well exaggerated.' As regards the land floods of the Upper Thames, it has been estimated by Mr. Symons, to show the impossibility of providing reservoirs, thatstorage would be required for 160,000,000,000 gallons, or for 714,285,714 tons of water, equal to from three to four times the daily ordinary tidal volume from Teddington to

To show how exceptional were the tides of March 1874 andNovember 1875. it may be mentioned that high water at Dover and Ramsgate attained on the 31st of January, 1877, an altitude exceeding by 2 feet any previously recorded tide at theseharbours, and yet the high water in London was 9 inches and 13 inches lower than in the tides of March 1874 and November 1875, which thus attained that excesa in range whilst the sea-level was so much lower. The sudden change of wind from west to north-west, driving the sea up the Thames estuary,appeers to be the mostreasonable explanation of this remarkable anomaly.

'p)--' 'p)--' 1 Feet. Ins.' Feet. 1ns.l Feet. Ins. Feet. Ius. Feet. Ins. Dover : S.W. 1 .. 24 0N.toN.W. dinnry spring tides 1 Ramsgate : 7th 24 4 23 10 20 6 22 .6 26 0 On tide gauge . .) 10th 23 4 ...... LondonAbove : low-water or-}, .. 1 21 3 i{gdek\ ard . . . .

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. 86 NINUTES OB PROCEEDINGS. Gravesend. Thewinter floodof 1875, at Windsor, taken by Professor Unwin, ASSOC.Inst. C.E., amounted to 14,102 cubic feet per second, or to 33,723,925 tonsdaily, so that Mr. Symons' estimate of storage would be for twenty-onedays of the great flood. The ordinary winter flood at Windsor amounts to 746 cubic, feetper second, orto 1,798,392 tonsdaily, or to of thegreat flood of 1875 ; and the ordinary dailydischarge at Twickenham is 3,250,000 tons. At Kingston the maximum discharge in 1866, as given by the Water Supply Commissioners, amounted to 8,000,000,000 gallons, daily, or to35,714,285 tons. Other floods occur, of from 22,322,OOQ tons to 26,785,000 tons daily. The average tidal volume of extreme tides above bridge is, as. before stated- 14,750,000 tons; and below to Grawsend = 92,730,000 ,, or 107,500,000tons for one tide,

Or 215,000,000 ,, daily ; to .322,500,000and to tons,' including 50 per cent. added for equinoctial spring tides, and es- ceptionally high ranges, due to great gales of wind, so that the land flood water is approximately one-ninth of the tidal water, or rather one-eighteenth, as one-half passes off on the ebb ; and a depth of 3 inches to 34 inches of the great metropolitan tide of 4 feet 9 inches above Trinity standard was due to flood water, Le, of the 3 feet 3 inches above the estimated Admiralty range.

' Comparing recent great tides, the following are the results:-

- Wind

Feet. lnchcs. Feet. Inches 20th March, 1874 . . . 44 22 North-west. -7*l 15th November, 1S75 . . . 1 49 ~ 33 Gale ; west. l 13thMarch, 1S7G . . . . 39 Gale ; west to north. ~ 26 2nd January, 1877 . . . . 43 1 34 Gale; west to north. l

The practical result is, that whereas hitherto a height of 4 feet has been considered the maximum required for the wharves, owing to the great increase of tidal volume consequent on the removal of

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. TEE CIVEB THANES. S7 Old London Bridge, the raising of high water andlowering of low water all the way to Teddington, and the additional range due to the embankments,a minimum height of at least 5 feetabove Trinitystandard is nowrequired for the metropolitan quay surfaces.

EFFECT OF EMBANKMENTS. The effect of the embankments has undoubtedly been to raise the level athigh water &thin the metropolitan area above bridge. The amount is estimated by the Author at from 4 inches to 6 inches. On the aut>hority of Mr. Leach, at Teddington the tide of the 20th of March, 1874, made the same height as at West- minster,reaching an altitude of 4 feet 4 inches above Trinity standard, rising above the land water 18 inches, giving.7 feet rise of tide and flowing up to Kingston, whcre the oscillation of tido was 12 inches;and this tide attained a greater elevation at London Bridge than atGravesend by 20 inches. The morning andafternoon tides of the 8th of April, 1874, both rose 21 inches higher at Blackwall than at Gravesend; 10 inches higher at London Bridge than at Blackwall; and at Westminster and Lambeth 4 inches higher than at London Bridgo.

INCREASEDDEVELOPMENT OF TIDE. The high tide of the 18th of March, 1874, was higher than the heightsgiven in the Admiralty tide-tables, by 2 feet 2 inches at Blackwall, and 2 feet 5 inches at London Bridge ; the tide of the20th of April, 1874, risingto the calculated height.The average of thetwenty-four annual maximum spring tides, as calculated in the Admiralty tide-tables forSheerness and London, shows how greatly the river hasbeen developed of late years:-

Yew. 1 Sheerness. I London. 1 - I Feet. Inrhes 1849 16 4 19 9 1869 16 4 20 6 1 Increased spring mnge 1874 16 2 209 47 j I} at London. 1876 16 If 1877 16 2

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. S8 IvIINUTES OF PROCEEDINGS. In 1799 the range of springs at London Bridge, as ascertained by Russell and Gream for theTrinity Corporation, was only 15 feet ; so that, in the last three-quarters of a century, the increased oscillation is 5 feet 9 inches. Of the increased range of 4 feet 7 inches as compared with Sheerness, 3 feet 10 inches are dne to the elevation of the surface at high water, and 9 inches to the depression at low water.

TABLE5. To illustrate the manner in which the tide has been developed in the Portof London, an abstractis given of the Admiraltymaxi- mumcalculated spring ranges for Sheerness and London, from 1845 to 1877, inclusive. It will be seen that at Sheerness the range of spring tides is from 16 feet 10 inches to 17 feet 6 inches, and atLondon from 19 feet 11 inches to 22 feet 3 inches ; and that thegreater range at London than at Sheernessincreases from 3 feet 1 inchto 4 feet 9 inches;and as there is but 3 feet 10 inches fall at high water, low water must be 11 inches lower than at Sheerness for a large number of tides.

TRINITYSTANDARD. Trinity standard,fixed in 1800 by the TrinityCorporation (39 & 40 Geo. 111. c. 47, S. 55), is 12 feet 6 inches above the Ordnance Survey datum of the mean level of the sea, which is 5 feet on the Old Dock sill at Liverpool. The Admiralty datum for low water of springs at Liverpool is 7 feet 9 inches, or 8 feet below the said sill. In London the present Admiralty IOWwater of springs is 20 feet 1 inch below Trinity standard. The inscription on a stone let into thelower external wing wall of theHermitage entrance to the London Docks states, “Low- watermark is 17 feet & 10 ins. below the lower edge of this stone, settled by theCorporation of the Trinity House Augt. MDCCC. -Vide 39” & 40” Geo. 3rd, Cap. 47, Sec. 55.” This was the Act for the formation of the London Docks, the pioneer measure afterthe inquiry of 1799. Sec. 54 defined the depth of the docks to be not less ‘‘ than within 15 inches of the level nf the river at low-water mark,” and sec. 55 said, ‘(the same shall be settled and determined bytwo of the Elder Brothersof the Trinity House, within three calendar months next after the passingof this Act, who shall certify the same in writing under their hands and seals.”

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. THE RIVER THAMES. 89 This standard high water from which the low water was mea- sured is, 28 feet on the St. Eatharine’s Dock sill; 22 feet 10 inches on Wapping entrance, London Docks, sill ; 25 feet 4 inches on that of upper old Shadwell entrance of London Docks where tides are kept ; 23 feet S& inches on that of Limehouse entrance of South West India Dock ; 24 feet 7 inches on East India Dock sill. In the Minutes of Proceedings Inst. C.E., vol. ii. (1843), p. 87, the London Dock Act is referred to as 39 & 40 Gm. III., cap. 17, instead of chapter 47.l HALF-TIDELEVELS. The mean level of the sea at Harwich, asdetermined by Captain Parsons, of H.M. ship ‘‘ Porcupine,” is 11 feet3 inches below Trinity datum, or 1 foot 3 inches higher than at Liverpool, and 11 feet 23 inches below Trinity datum atSheerness, as determined by tidal observations at H.M. dockyard, or 1 foot 3+ inches higher than atLiverpool, and 10 feet below Trinity datum in the Portof London, from t,idal observations at the London Docks, or 2 feet G inches higher than atLiverpool.

SHEERNESSAWD LOXDOWLow WATER DIFFERESCE. Taking the mean spring ranges in London and Sheerness re- spectively, as worked out in the Admiralty tide-tables, as 20 feet 8 inches and 16 feet, or 10 feet 4 inches and 8 feet half range, the difference of low water stands asfollows :-

London. Sheerness. Difference. - - - Feet. Inches. Feet.Feet. Feet. Inches. Foot. Inch. l04+1O-S+112~=11~

i.e. so much lower in London. Theaverage is, however, really less, as shown by Table 6. Mr. Lloyd, in the “ Philosophical Transactions ” for 1830, by abstracting certain tides,worked out the result that low water

Without explanation, it would appear anomalous that the Elder Brethren of the Trinity House should have fixed the standard of reference for the level of low water, by a stone let into the lower wing of the Hermitage entrance, within threemonths after the passing of theAct for a contemplated work. The Hermitage entrance was formed on the site of an existing graving dock bearing that name, the lower wing of which (Hoare’s Wharf) forms the present eastern boundary of theentrance lock forebay, and thePortland stone tablet with inscription is there now, and another above the old Shadmell entrance near the Pelican ” Stairs.

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. 90 MINUTES OF PROCEEDIKGS. springs, low water neaps, half-tide level, high water neaps, and highwater springs were allrelatively from 1 foot 8 inches to- 2 feet 3 inches higher at London than at Sheerness. But to get these results he took 17 feet 8 inches as the range of springs at Sheerness from dockyard tables kept for three years prior to 1830. Yet at the present time, and as far back as the Admiralty tide- tables are published, the estimated spring rangc is 16 feet; this difference of 1 foot 8 inches, added to that found by Mr. Lloyd, agrees with the calculated and observed results of the present day. Besides this, although his mean high water at Sheerness agrees with that of the present day, his mean London high water W-as 18 inches lower, and the mean London high water was then as now 12 inches below Trinitystandard, as shown bySir John Lubbock, and not 2 feet G inches as by Mr. Lloyd. Plate 2, deduced from theAdmiralty tide-tables, shows as between London and Sheerness at. the present day, a very high ascending gradient at high water of spring tides, somewhat less for neaps, a much lower gradient for half-tide level, a plane at low mater, but under certain conditions low water 12 inches to 2 feet lower in the Portof London than at Sheerness. Table 7 illustrates this by certain tides at the London Docks, and at thedockyard at Sheerness.

GRAVESENDLow WATEE. The neap low water is not really a plane or dead level, nor the low water springs, as it will be seen low water at Gravesend is lower than in London by 9 inches, and lower than at Sheerness by nearly 12 inches, thefall at low watercontinuing below Gravesend, untilmet and overcome bythe young %ood from Sheerness.

SHEERNESS, GRAVESEXD,LONDON, CHELSEA, AND BATTERSEAHIGH WATER.-TABLEG. A comparison of tidal observations over a series of ten years, 1833-1843, at Sheerness,Gravesend, the London Docks, Chelsea, and Battersea, taken by various authorities, shows the following . results :-The high-water level for the mean of two years of these tides was 1 foot 5 inches higher at Gravesend than at Sheerness, a distance of 21 miles, with a difference of time of half an hour, or later, high water at Gravesend. The high-water level at London

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. THE RIVER THANES. 91 for the mean of the whole of these tides was 3 feet G2inches higherthan at Sheerness, a distance of 48 miles, with a difference of time or later high water in the Port of London of one hour and a quarter.

SITEERNESS dND LOXDONTIDES.-TABLE 6. Table G shows that from 1833 to 1843 low-water level was. comparativelythe same at London and Sheerness. Thepresent level is now undoubtedly lower at London than a corresponding tide at Sheerness, amounting to from 5 to 13 inches for average springs. This difference is much greater taking single tides, as shown byTable 7 of comparisons. The whole years' tides,one with another, show the " normal " difference at high water to be 3 feet 8 inches to 3 feet 10 inches, and low water is practically the. same, or 4 to 5 inches lower in London. These differences amount to from 4 feet to 5 feet at high water and to 2 feet G inches for a London low water lower than the corresponding tide at Sheerness,. the greatest fall atlow water also amounting to 2 feet 6 inches. The spring and neap high waterdifferences vary from 6 feet to, 2 feet. The maximum difference of rangein favour of London amountsto G feet 7 inches, butusually 4 feet to 5 feet. The. minimum high water difference is from 2 feet to 2 feet G inches with small neap tides, and the maximum 4 feet to G feet with great spring ranges, greater elevation of high water in favour of' London. Exceptional tides resultant on sudden gales of wind are not taken into account. Under exceptional conditions of weather great variations occur. On the 18th of February, 1836, with a strong north-east gale, themorning tide was only 7 inches lower at Sheerness than atLondon, with 14 inchesfall at lowwater. Again on the 18th of April,. 1838, the afternoon high water was only 1 foot 11 inches lower at Sheerness than in London, where low water was 13 inches the- lowest;this occurred with a strong north-west wind. These cases might be multiplied;the comparisons quoted are for the. same tide ateach place. Sheerness is situateon a tidal estuary, themouth of the river in effect, 5 miles in width. At Gravesend the width is only 3 mile ;. but in the Portof London, although the distance from Sheerness is nearly three times as great, the width of the channel diminishes. gradually upwards, and the river through London is nearly one- half the width it is at Gravesend. This, however, is somewhat qualified by the fact that the river diminishes rapidly in width above Gravesend; as between the upper part of Northfleet and

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. 92 HINUTES OF PBOCEEDINGS. Tilbury Ness, 2 miles above Gravesend, it has lost one-third its width, and is there only wider than in the Port of London by one-half of the mean width of the channel. It widens, however, again in thetwo upper reaches to the same width as at Gravesend over a course of 4 miles,and hence upwards diminishes with tolerableuniformity. The absolute level of the surface of the tidal column at high water must varyfrom a regularly ascending gradient due to thesecauses.

LEVELOF HIGHWATER ABOVE BRIDGE.-TABLE6. This is forcibly illustrated by a series of tidal observations, by Mr. Simpson,of the high-water levels in Chelsea Reach in 1841-43, and by those taken for the Metropolitan Sewers Commissioners in 1849. The result of these observations proves that at that period a depression at high watercommenced just above Westminster, for &h, Simpson’s readings made highwater 43 inches to 6 inches lower at Chelsea, and those of the Sewers Commissioners 12 inches lower at Battersea Bridge than at London Bridge, and the low- water level 15 inches higher.

PRESENTHIGH-WATER LEVELS. That this high-water depression does not now exist is certain, as the great tide of the 20th of March, 1874, made practically a pondlevel, being 4 feet 4 inches above Trinitystandard at Teddington Weir, as it was at Westminster, and the tide of the 18th of April, 1874, which onlyrose to within 8 inches of Trinity standard at the GravesendTerrace Pier, i.e. so much below it, rose to 14 inches above it at Blackwall, 2 feet at London Bridge, 2 feet 3 inches at Westminster and Lambeth, and 2 feet 4 inches at Richmond, in effect regularly ascending at high water. If causes existed prior to the erection of the modern Thames Embankments, in thesudden widenings of the river above bridge, to produce a lowering of the surface of the tidal column, the above facts show that it has been removed by these works. If, in raising thetidal surface,these works have produced some temporary trouble, they have at the same time proved self-compensating, and requiring no tidal accumulating reservoirsto store up water formerly overflowing the mud foreshores. A consideration of the above will show, that the estimate of compensation due to the embankments raising the surface of the tidal column might be largely increased, as the estimate of 6 inches was only taken above a plane, nothing

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. TH E RIVER THE THAMES. 93 being added for the fall of high water above Westminster, which tidal observations would appear to establish.

MODERNDEVELOPXENT OF TIDE. From Table 6 it will be seen that at Sheerness the high water has been (as adduced from the average of the whole years’ tides) 4 feet 8 inches to 5 feet 2 inches below Trinitystandard, and low water 18 feet 4 inches to 18 feet 9 inches below Trinity standard,giving a mean range for theentire year of 13 feet 7 inches. At the London Docks the high water has been 1 foot 5 inches to 1 foot below Trinity standard, and low water 18 feet 5 inches to 19 feet 3 inches below Trinitystandard, giving a mean range for the entire year of from 17 to 18 feet, showing that the tide ebbs much lower in the Port of London than in former years. METROPOLITANLOW-WATER CHANNEL. A comparison of the last issue of the Admiralty chart with those of earlier date shows that, due to the increase of tidal volume and dredging of shoals, the low-water deep channel has been extended upwards past Woolwich and Blackwall. There are, however, two artificial barriers to this continued extension upwards, or at least to its ayailability for navigation. The first is the ThamesTunnel,‘ which has only 8 feet depth of water over its crown at low water of spring tides, with a normal low-water depth above and below of; 10 or 11 feet;and the same at Waterloo Bridge, where, from artificially keepingup the river bed, bythrowing loose stone around the piers to prevent their being undermined, there is only under the sole low-water navigable arch, on the Middlesex side, 8 feet at low water, witha normal depth above and below of 10 to 11 feet. DEPOSITS. One important question has not yet been referred to, viz., in what way the altered conditions of the river have affected the de- position of silt which comes up with every tide, and which at an early period was checked by, and thus deposited below, Old London Bridge.Subsequently the wide reach at Hungerford, 1,200 feet across, afforded a resting-place for the deposit,which became obnoxious by the continued lowering of low water.

From Mr. Hayter’s remarks (p. 129) there would appear to be a minimum thickness of ground above the tunnel of 16 feet below the river bed.4. B. R., 27 June, 1877.

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. ‘94 NINUTES OF PROCEEDINGS. Undoubteclly certain accumulations have increased of late years. In the Pool more mud is said to gather on the foreshores ; on the Surrey side above and below Waterloo Bridge the mud increases ; -also in front of St. Thomas’s Hospital;and the wharfingers of‘ Millbank complain of deposit, which may also be observed on the Middlesex shore along theface of the Embankment,between West- minster and Waterloo BridgeE. Many of these alluvia are local, ,caused by rapid recessions and projections, and no doubt admit of mitigation. But the generalquestion of disposing of the mud must necessarily become a larger one the more the embankments are .extended.

RELATIVEHIGH-WATER LEVELS, SHEERNESS AND LONDON.- TABLES7 AND 9. With the information yearly published by theGovernment, the real hydraulic condition of the river should be better understood. A cursoryexamination of theAdmiralty tide-tables, andthe journalskept at the London Docks, andat H.M. Dockyard, Sheerness, will show that Mr. Lloyd underestimatedthe difference athigh water fromSheerness to London bynearly one- half,and yet his results are unquestioned, and conclusions are frequently based on them. The late Mr. Beardmore, M. Inst. C.E., in January 1856, stated at the Institution,‘‘ The mean high water taken atLondon Bridge for one month in 1849 by the Metropolitan Sewers Commissioners was 1a02 foot above that of Sheerness takenin 1827-8-9.” In effect this comparison yields not much more than one-fourth of the .actual difference. He stated at the same time that the low-water difference was 6 inches, and was lowest in London. He adds, however, that the mean ranges were, London, 17* 578 feet ; Sheerness, 14.472 feet. The difference of range would, therefore, be3.106 feet. The low-water difference Mr. Beardmore gave as 0.598 foot, so that by only one month‘s observations, taken for the Metropolitan Sewers Commissioners, the high-water difference was really 2.508 feet. But theSheerness range was overestimated,and the high-water difference, therefore, too low. The real high-water difference for the whole years’ tides for eleven years, 1833-1843, in Table 6, was 3 feet 62 inches ; and for the three years1873-74-75,3 feet 10 inches. It will thus be seen that there has been a gain of 3 inches of late pears, due to the moderndevelopment of tidal momentum above bridge. The Author had an opportunity of observing the highest tide

af thepast year at Harwich, on the afternoon of the19th of September last,which flowed 8 feet Y inches above Ordnance datum, or 3 feet 9 inches below Trinity standard. At Sheerness the same tide was, by Admiralty Dockyard measurement, 3 feet ,6 inches below Trinity standard; and at the London Docks, by Captain Maitland it was 1 foot 7 inches above Trinity standard, and only 1 inch higher than the Admiralty calculated height. So thathigh water of that day in Londonwas relatively 5 feet 4 inches, and 5 feet 1 inch higher than at Harwich andSheerness. In effect, amean spring tide high water difference. Mr. James Walker,Past-President Inst. C.E., in a report of the13th of December, 1841, on the Thames Embankment question, accepted Mr. Lloyd’s results,saying: ‘‘ At present thelevel at high waterat London Bridge is 2 feet higherthan at Sheerness, a length of 40 miles; and at London Bridge it is, on the average of a series of observations, when the river was free from land floods, 1 foot lower than at Richmond Bridge,” &c. It is due to the late Mr. Thomas Page, M. Inst. C.E., to state that in his letter of the 1st of July, 1843, addressed to the then Chief Commissioner of PublicWorks, he directed attentionto the fallacy of results based on Mr. Lloyd’s, andgave the true state of the case in the following words:“The lcvel of high water at London Bridge above the high water at Sheerness was, for the month of February this year, more than 3 feet 10 inches, .and for the months of March and April sometimes 4 feet and even 5 feet higher than at Sheerness,” &c. The morning and afternoon tides at high water of the 2nd and 3rd of January last marked on the London Docks Shadwell tide gauge, as follows :-

Feet. Inches. Feet. Inclvs. Feet. Inches. Feet. Inches. 29 4 29 1 28 S and 28 5; or 4 0 3 9 3 4 ,, 3 1 abovo Trinity standard.

And on the Sheerness tide gauge:-

Feet. Inches. Feet.Inches. Feet. Inches. Feet.Inches. 10 9 10 5 9 S and 9 S; or 0 ci 0 10 1 10 ,, 1 7 below Trinity standard. ‘The London high water in each case being relatively highest in London by- Feet. Inches. Feet. Inches. Feet. Inches. Yect. Inches. 4 6 4 7 5 2,aud4 S The morning tideof the 2nd of January was also 3 feet 4 inches

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. 96 MINUTES OF PROCEEDINGS. above the calculated height by the Admiraltytide-tables, and this tide was 4 feet 3 inches above Trinity standard at Westminster. The continuous elevation of high water during these springs is due largely to the vast quantityof land flood water.

RELATIVELOW-WATER LEVEL, SHEERNESS AKD LONDON. Illustrative of this question, reference may bemade tothe Admiralty Chart NO. 2484, 1830-33, corrected to 1857-59, and to 1871, which has the following note :-

6‘ Datum.-Low-water average springs = 3 feet 3 inches on the tide gauge at the Wapping entrance to London Docks, or 19 feet 8 inches below Trinity H. W. mark. The low-waterlevel was transferred down the river from the above Datum, which is 1 foot 7 inches lower than a corresponding low water at Sheerness.” This closely approximates with a large number of tho rysults in Table 7. Also to the Admiralty Chart No. 1607, 1844, corrected to 1858- 61, and to 1871. Note :-“Datum of soundings being 8 feet on the index at the caisson at Sheerness, or 13 feet 2 inches below Lloyd’s brass plate on the south pier at theBoat-house Camber.” The effect of these notes is that- Feet. Inches. Low waterin London was ..... 19 8 below Trinitystandard. And at Sheerness 11 feet 3 ins. + 8 feet = 19 3 ,,,, Or a lower London low water of ... 0 5, instead of 1 foot 7 inches. But low water is now 2 feet 9 inches on’ the sill of Wapping entrance of London 3 3, or 6 inches lower. Docks, in lieu of ...... I Therefore London low water is now lower than atSheerness by ...... } 011

This is shown by the Admiralty Monthly TideTables ; the first Chart note remains, as, if altered, it would affect the soundings throughout to the extentof 6 inches. Feet. Inches. Admiraltyhalf-spring rangein London = .....10 4 Mean-tidelevel below Trinitvstandard ...... 10 0 Low-water springs below Trinitystandard ..... 20 4 Admiraltyhalf-spring ranges atSheerness = .... 8 0 Mean-tidelevel below Trinitystandard ...... 11 3 Low-watersprings at Sheerness below Trinitystandard . 19 3 London low-watersprings lower thanat Sheerness by . . 1 1 There is, therefore, a difference of only 2 inches in thetwo

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. THE RIVER THAMES. 97 Admiralty computations, i.e. theCharts make the London low water relatively lower than at Sheerness, 2 inches less than the yearly tide-tables. Reference to Table 6 will, however, show that practically, taking the whole years’ tides for 1873,1874, and 1875, the mean low-water difference of theentire year is only 5 inches, and lowest in London; although a large number of tides may be selected showing a much greater difference. A low ebb of the 21st of September last (A.Y.) was 20 feet 1inch below Trinity standard at Sheerness, and 20 feet 6 inches at the London Docks ; or 5 inches lowest at the last,indorsing the results in the last AdmiraltyChart. On the 2nd and 3rd of January last, however, the morning low waters at the Shadwell entrance of the London Docks were 7 feet 6 inches and 7 feet on the gauge, or 17 feet 10 inches and 18 feet 4 inches below Trinity standard. And on the Sheerness tide gauge 7 feet 3 inches and 8 feet 3 inches, i.e. 18 feet 6 inches and 19 feet 5 inches below Trinity standard. The Sheerness low waters were therefore relatively lower than in London by 8 inches and 1 foot 1 inch; this comparative elevation of low water being also due to the enormous quantity of land water coming down,

GENERALQUESTION. The subject of the present Paper must be of great public interest, and when the sanitarycharacter of the river, makingLondon as it does one of the most healthy and beautiful cities in the world, and its being the vehicle of the greatest commerce the world perhaps ever saw, are considered, the conclusion is pointed to that it is one of vastnational importance. No doubt the whole question demands, and will receive, continued and greater attention and consideration;the above facts andthe inferences drawn therefrom are offered as an instalment towards its illustration. The combined causes of the altered modern condition of the river,viz., the removal of old London Bridge, that of Blackfriars and Westminster, the systematic dredging of shoals bringing the tidal deep low-water channel higher and higher up the rirer, and the modern embankments, have brought high-waterlevel in thePool to thesame height at Teddington, and correspondingly lowered the low-water level and scoured the bed. These accumulated causes, producing results of comparatively slow and gradual operation, becoming more and more intensified each year, during nearlyhalf a century have added [1876-77. N.s.] I1

Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. 98 MINUTES OF PROCEEDIXGS. about 33 per cent. to the above-bridge tidal volume operating twice every twenty-four hours, thus showing how altered the metropolitan condition of the river now is, and how great are thebeneficial results in a commercial and sanitary view, attended, however, by the comparatively lesser evils arising from the non-embankment of the low-lying portions of the metropolis, and which, as these tidal improvements are developed, will be intensified year by year until met by some well-considered and comprehensive measure.

The communication is accompanied by a series of diagrams, from which Plates 2 and 3 have been in part compiled.

APPENDIX.

TABLE1.

Drainage Tributaries. 1 'rota1 Areas. Lengths. i Lengths. ---Mileage. square miles. Miles. aliles. Thames ...... 5,162 463 661 Severn ..... 4,437 178 I 453 I 631 Ouse, Yoiksiire .... 4,207 592 1 5804 G40 i 201 Trent...... Derwent ...... -- -- Total Trent and Derwent. 3,972 l 232 , 331 i 563 .Ouse, Great, to Wash ... 2,894 369 Wye ...... 1,655 371 Mersey ...... 1,706 256 Humber...... 1,229 93 Nene. .... I.. 1,055 110 Witham ....S.. 1,052 164 Tyne...... 1,053 190 Medway ...... I 997 131

TABLE~.-RIVEB THAMES,GBAVESEKD. Two TEARS'TIDES. Means of each month's daily readings. Zero of tide gauge 22 feet below Trinity standard. 1843. 1844. H.- W. L.- W. n.- W. L.- W. Feet. Ins. Feet. Ins. Feet. Ins. Feet. Ins. January ... 19 2 17 l8 4 29 February. .. 19 5 32 8 18 25 March. ... 19 1 24 19 0 24 April. ... 18 6 28 6 18 26 May .... 18 7 28 7 18 27 June .... 1810 31 6 IS 30 July .... 186 2 11 18 I1 2 10 August ... 18 11 1 l1 5 19 27 September . . 18 10 27 19 0 24 October ... 188 2 11 18 8 2 10 November . . 188 30 9 18 29 December . . 18-8 -26 -18 4 34 Mean .... 18 10 Ranges ...... Below Trinity standard 22 feet 32 19 5 19 4 on gauge . . 3 range below do. 11 3$ 11 34 H? Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. 100 WZPTES OF PROCEEDINGS.

c -..3 ...... mwww ...... z1 -d...... mm030 ...... L Y mmmm

OQ, 4::::::::::::: .... Q m-

TABLE7.-RIYER THAMES. HIGHWATER and Low WATER COMPARISONS BELOW TRINITYSTAXDABD, as OBSERVED. N.B.-In the following Tables the high-water levels marked thus * are above Trinity Standard; and the low-water differences marked thus * are lowest in the Port of London. The mark t denotes strong wind. - - -

L~NDON. Diffe Differ Differ ence I ence a ence o H. M L. W. Range H. W. ~ L. W. 1 Rang pt. Ins. Ft. Ins. Ft. In Ft. Ins. Ft. Ins. Ft. In Ft. h Ft. In Ft. In 1833 (W. byN. June l1 P.M. 7 9 l8 7 10 10 l0 318 4 8 1 2t 03 29 Gale. Aug. 18 A.M. 1 7* 19 1 208 2 119 617 5 3t 05 33 N.W. Oct. 14 A.M. 0 4*2010 212 33 22 1 18 10 3: 13 24 W. by S. ,, 15a.~. 2 4*19 2184 1920 118 4 41 09 34 W.S.W.t Nov. 21 P.M. 3 11 16 4 12 5 6 8 15 7 811 21 09 36 Dec. 10 A.M. 1 11*,1710 19 9 2 416 S14 4 4: 12 55 W. t ,, 20 P.M. 5 4 1810 13 6 7 10 18 2 10 4 2t 08 32 1834 Jan. 3 P.M. 2 7 '20 4 17 9 6 3 20 11 14 8 36 07 31 ,, 29~.~.3 7*(16 2072 0 4*15 11 16 3 32 08 3 11 N.N.W. Mar. 5 A.BX. 4 11 9 8 717 7 9 0 3c 03 29 to P.M. 5 7 117 Sept. 7 A.M. 1 9*1s 10 20 7 2 019 717 7 3s 09 30 S.S.W. Oct. 24 P.M. l14 11 11 1 14 9 8 10 0 23 23 ,, 25 A.M. 3'io 1 .. 5'il 2-1 .. .. Dec. 1A.M. 1 9 19'io ~"139 02 37 W. Gale. 1835 April 16A.M. 3 10 09 31 N.N.W. May 14a.~. 44 11 33 E. t June 19P.M. 32 05' 37 N.N.W. July 21 P.M. 37 03 34 Aug. 19 P.M. 33 04 2 11 E. Sept. 17 P.M. 32 01 31 ,, 25 A.M. 39 07 32 W.S.W. Oct. 26 P.M. 41 0 4' 45 Nov. 28 P.M. 37 02 35 Dec. 20 A.M. 38 09 2 11 E.t ,, 28 P.M. 32 Level 32 W.N.W. 1836 Jan. 23 P.M. C 1 '21 7 17 6 6 11 20 5 13 6 2 10 1 21 40 ,, 28 P.M. t 8 113 7 10 11 5 G 13 4 710 210 0 3* 31 Great Feb. 18 A.M. 1 1 ,l6 1 16 0 0 817 316 7 D7 12 D7 N.N.E. Gale. May 24 P.M. 30 3 1' 31 Oct. 2 P.M. 29 3 01 59 W.S.W. ,, 27~.~. 32 3 5* 37 W.t Nov. 3 P.M. 25 3 11* 34 ,, 10 A.M. 35 1 4* 39 Dec.2 P.M. 31 12 1 11 N.E. to ,, 2Ga.~. 2 013 G11 6 16 15 l1 E.N.E. li Gale. Downloaded by [ UNIVERSITY OF IOWA LIBRARIES] on [15/09/16]. Copyright © ICE Publishing, all rights reserved. SHBEBHESS. Differ. Differ- Differ- ence ul ence at ence o H. L. W. Range Range m. _-.I -- Ft. Inr l3%. Ins./ Ft. Inr Ft. lnr 't. Ins 't. Ins. Ft. Inr 1837 3.; 't. Ins.1 Ft. Ins.' I Feb. 15 P.M. 3 10 116 10 13 0 7 3 ,l6 9 96 35 0 1*3 6 May 13 P.M. 4 10 ,l6 10 12 0 7 9 '16 0 83 2 11 0 10* 3 9 ,, 22A.M. 0 9*19 1 19 10 2 8 ;l9 4 16 8 35 03 32 N.byW.t June 10 P.M. 3 717 413 9 6 5 ,l8 5 12 0 2 10 1112w.s.w.t ,, 12 P.X. 3 6 117 1 13 7 6 6 !l6 9 10 3 30 0 4*: 3 4 Sept. 10 P.J.I. 3 3 16 713 4 F 5 '16 7 10 2 32 Level 1 3 2 Nov. 12 P.X.' .. 17 10 20 0 .. l5 8 14 1 39 2 2*' 5 11 N.N.W.t to A.M., 2 2* .. 17' .. .. Dec. 21 P.M. 3 4 16 G 13"2 6 11 '16'io 9 L1 3-7 04 33

1838 Jan. 18 P.M. 2 3 17 1 1410 5 10 i17 4 11 6 37 03 34 Feb. 16 P.M. 0 616 115 7 4 617 0 12 6 40 011 3 1 ,, 27 A.X. 1 11 '21 0 19 1 40 2 2 l10 S.E.t Mar. 5 P.M. 7 3 '15 F 83 34 0430 ,, 20 P.M. 9 10 '18 0 82 30 0 2*3 2 April 4 Pm. 7 1 '15 2 81 28 0 5*3 1 ,, 18 rx 6 3 16 7 110 4 8 2 :l5 6 74 1 11 11*3 0 N. W. Oct. 12 P.M. 3 3 14 5 111 2 5 313 4 81 20 11*3 1 N.W.t ,, 27 P.M. 5 8 17 7 !l1 11 8 10 '17 3 85 32 0 4*3 6 Dec. 4 P.M.' .. 1710 '19 5 .. '18 9 16 6 3 10 0 11 2 11 W. to A.M.J 1 7* ......

1839 Jan. 8 P.M. 3 116413 3 91 2 11 13*4 2 ' N.N.W. Feb. 10 P.M. 6 1 11410 ~ 8 9 8 4 '13 4 50 23 16*3 9 t0N.N.E. ,, 15 A.M. 2 0*(17 7 19 7 1 11 17 9 15 10 3 11 0239W. by N.i ?, 23 p.nI. 2 8 '16 4 ,l3 8 6 4 115 10 96 38 0 6*4 2 Nar. 15 A.M. 2 7 22 2 '19 7 6 621 6 L5 0 S 11 0 8*4 7 ,, 24 P.I. 2 9 15 2 '12 5 7 0 'l5 3 83 43 0142 lfay 14 A.M. 1 9*,19 4 21 1 2 0 '19 1 L7 1 39 0 3*4 0 N.N.E.t S.W. July 18 P.P. 3 5 I17 2 /l3 9 6 1 17 11 L1 10 28 0 9 111 Gale. Aug. 20 P.M. 4 0 115 11 ill 11 F 715 6 8 11 27 0 5*3 0 Sept. 18 P.M. 4 4 'l5 10 l1 6 7 11 16 2 83 37 04 33 Oct. 30 1'.nI. 1 4 '15 1 i13 9 5 3 ,l6 5 l1 2 3 11 1427 Dec. 22 p.ar.1 2..2 j18 0 /20**2 19 3 l7 4 41 l3 210 w.s.1v.t to P.31.j .. z'il 1 .. .. ,, 29 A.M. 2 7 16 1 ,l3 6 6 316 3 l0 *.0 38 O"2 3"6

1840 i Jan. 29 P.M. 2 7 '15 2 '12 7 6 9 '15 4 87 42 0240 Feb. 18 A.X. 0 10*18 6 19 4 , 3 8 20 8 ,l17 0 46 2224 ., 26 P.M. 4 8 116 7 111 11 i 7 6 !l5 11 i 85 2 10 0 8*3 6 Mar. 19 A.M. 0 10*,19 1 .l9 11 ' 2 7 20 3 L7 8 35 1223E. April 4 A.X. 1 6* 20 0 '21 6 3 6 '20 8 17 2 50 08 44 E.N.E.t May 22 A.11. 1 3 117 2 '15 11 , 4 4 16 7 L2 3 31 0 7*3 8 June 3 AX. 0 7*119 7 ,20 2 1 3 3 ,l9 9 L6 6 3 10 02 38

TABLE RIVER THAMES.HIGH WATER and Low WATER,&c.-continued.

SHEERXESS. Diffcr- Differ- Differ- - snce al ?nce at ence of H. W. L. W. Range. ----H. W. 1 L. W. I Range. Ft. Ins. Ft. Ins. 'Ft.Ins Ft. Ins. Ft. Irm Ft. Ins Ft. Int ?t. Ins.' Ft. Inr 1840 l July 2 A.X. 0 10*!19 8 20 6 2 919 116 4 37 0 7*, 4 2 ,, 31 A.M. 0 9*1810 19 7 2 918 916 0 36 0 l*, 3 7 Aug. 7 P.N. 3 11 117 2 13 3 6 10 15 9 8 11 2 11 1 5*, 4 4 ,( 18 P.771. 0 821 420 8 3 4 '18 11 l15 7 28 2 5*1 5 1 ,, 29 A.% 0 10* 19 2 20 0 2 919 316 6 37 0 113 6 Oct. 19 P.X. 0 915 915 0 3 2 14 10 11 8 25 o 11*( 3 4 f W.S.W. Nov. 14 P.I. 0 10 21 1 20 3 4 117 213 1 33 3 ll*, 7 2 Gale. ,, 21 A.M. 5 0 18 10 13 10 7 G 18 3 (10 9 26 0 7*~3 1 1841 l Jan. 10 P.M. 0 10 21 4 20 6 4 3 '19 11 ,l5 8 35 1 5* 4 10 25 A.M. 0 9* 18 4 19 1 2 10'19 1 '16 3 37 0 91210 .F&. 15 P.M. 3 8 15 6 111 10 7 4 l15 10 I 8 6 38 0 413 4 Mar. S A.M. 1 7*19 7 l21 2 2 7 120 7 18 0 42 1 0;3 2 W.N.W. ,, 9 A.M. 0 S* 20 6 21 2 3 6 /20 8 17 2 42 0 214 0 April 6 A.IVI. 0 11*20 4 121 3 3 320 016 9 42 0 4*( 4 6 E. to N.E. ,, 15 P.M. 4 10 115 10 ~110 7 9115 5 7 8 2 li 0 5*' 3 4 May 20a.~. 4 719915 2 37 0 11* 4 6 June 3 A.Y. 4 7 18 11 14 4 47 July 22 A.M. 2 919516 8 3 11 8 :*' 4 8 Aug. ~A.N. 5 6 19 3 '13 9 35 1 3*8 4 6 ,, 18 A.M. 42 0 5*4 7

1842 Jan. 20 P.M. 4 3 18 2 113 11 30 0 8*3 8 Feb. 28 P.X. 1 3*21 1 22 4 44 2 1'1 6 5 S.W. Mar. 21 P.Y. 4 9 '18 1 13 4 2 11 2 2*i 5 1 N.W. t0N.t ,, 28 A.M. 1 5*20 4 21 3 40 0 1*4 1 W.N.W. April28 A.M. 0 S* 19 4 20 0 42 0 713 7 May 3 P.x. 4 4 118 4 14 0 2 11 1 10* 4 9

I 843 Jan. 1 A.M. 1 5*18 1 ,l9 6 1 10 16 6 114 8 33 1 7* 4 10 1 N.N.W. Feb. 4 A.M. 2 9*j14 1017 7 0 816 215 6 35 1421t0N.N.E. I l Gale. Mar. 11 P.M. 4 11 16 10 111 11 7 10 116 11 9 1 2 11 0 1j210 April 17 A.M. 1 8*19 7 '21 3 2 320615 3 3 11 011'3 0 E. .July 22 P.X. 3 11 17 4 113 5 32 0 5*3 7 Sept. 26 A.Y. 2 3*118 9 21 0 39 0 513 4 N. by W. Oct. 18 A.x.) .. .. to P.nf. J 2--3 0 10*; 3"l NOV. 22 A.X. 35 0 2*Y 7 ,, 23 A.Y. R 11 0 513 G UT.R.W.t ,,, 30 P.41. 3 11 18 6 14 7 7 5 18 6 '11 1 36 Level I 3 6 Dec. 1 P.M. 3 015 9 12 9 6 O!l5 619 6 30 0 3*, 3 3 ,, 2 A.M. 4 018 214 2 7 0 16 11 ' 9 11 30 1 3*; 4 3 ,, 23 A.M. 1 10 ,20 1019 0 5 6 820 3 l14 9 38 0 7*1 4 3

TABLE7.-RIVER THAXES. HIGHWATER and LOW WATER. &c.-continued.

LONDON. SHEEFXESS. Differ- Differ- Diffw- ?Ice at ?Ice at ence of - Q 8. W. L. W. Range. ---H. W. L. W. Range. -_ l __- 't. Im. Ft. Ins./ Ft. Ina %.Ills 8. Irt. Ins. Ft. Ins 1873 Jan. 8 P.M. 2 017 715 7 47 011 3 8 ,, 23 P.M. 1 7 16 10 h5 3 5 11 117 0 11 1 44 0242 Feb. 7 P.M. 82 16 4 113 8 6 5 116 7 l10 2 39 03 36 ,, 15~.~.0 520 620 1 4 5 120 1 15 8 40 0 5*4 5 Mar. 8 P.M. 3 8 1510 12 2 8 117 4 e 3 45 1 G 211 April 6 P.M. 3 515912 4 7 10 115 4 7 6 45 0 5* 410 ,, 20 P.M. 2 817 414 8 6 6 /l7 9 11 3 3 10 05 35 ,, 28 A.M. 1 7*20 11 22 5 3 1 19 1016 9 48 11*5 9 E. May 19 P.X. 2 5 117 10 15 5 5 9 '17 0 11 3 34 ,, 28 A.M. 0 11*19 8 20 7 3 9 ;l9 5 15 8 48 N. June 19 P.M. 22 118 167 5 6 3 i18 3 12 0 41 26 A.M. 0 10*119 4 20 2 3 8 '19 8 16 0 46 JGJ' 12A.M. 0 11*20 0 20 11 4 0 l20 3 16 3 4 11 S.W. Aug. 4 P.M. 3 9 17 7 13 10 7 0 117 0 !l0 0 33 0 7*. 3 10 ,, 18 P.M. 176 2 414 10 7 4 :l9 9 12 5 4 10 2 5l2 5 Sept.9 A.M. 1 8*12O '226 2 3 0 .20 9 179 48 o 314 5 W.S.W. NOV. 7 A.M. 1 0*'20 0 I21 0 2 7 l9 9 ,l7 2 37 0 3*1 3 10 ,, 21 A.X. 0 3* 19 6'19 9 3 1019 4 115 6 41 0 2*,4 3 Dec. 16 P.M. 1 10*19 1 20 11 1 189 1 116 4 37 1 O*' 4 7 ,, 21 A.M. 0 5 19 5 119 0 4 020 316 3 37 01012 9 ,, 22 A.1. 0 11 20 8 199 3 194 215 10 25 1 6* 3 11 ,, 28 P.M. 192 2 6 117 4 6 419 112 9 42 0 5*4 7

1874 Jan. 5 A.M. 0 10 20 4 l9 6 3 319616 3 25 0 10* 3 3 ,, ~A.M. .. 20 4 .. 0 1*l .. ,, 6 P.N. 1 0 .. 419 5"l 4"l l .. i 24 ,, 13 P.M. 4 717212 7 36 0 5*~3 11 ,, 20A.M. 28 7l16 '20..319 ,15**24 8 899 4 4,l6 0 6*, 104 S.W. ,, 27 P.M. 6 164 8 i10 4 32 0 11*,4 1 Feb.2 A.X. 33 20 1 1610 21 0 3*'42 N.W. ,, 3 A.M. 5 10 21 1 '15 3 52 1114 1 ,, 4 A.M. I 5 11 20 11 15 0 52 n si411 ,, 11 P.M. 97 18 9 '11 0 3 10 0 li ' 2 11 4 44 21 8 ~174 59 0 8'5 1 N.W. 4 7 21 8 l17 1 5 10 010'5 0 W. 8 318 910 6 24 1311 1 1 0 7 20 3'9 3 64 2 5 311 21 Il6 2 47 0 8'311 ,, 6A.M. 0 2 l9 4 '192 5 6 120 11 115 5 54 17!39 1 ~ ~ ,, 13 P.M. i 410 17 4(12 6 ' 8 3 117 5 ~ 9 2 35 o 113 4 1 8*20 6 122 2 i 3 1 21 3 '18 2 49 0 914 0 W.N. W. :: : .. 20 8 24 11 ! .. 121 3 20 8 4 10 N.W. to A.X.]' 4 3* 0 71 .. 1 .. ,, 21a.~.I 1 7*20"8/82'*3 3 '219 9 118 0 5-4 W. ,, 26p.~.8 4 19 9 ;l5 1 ' 7 11 172 1 9 3 33 April11 P.M. 3 5 16 2 i12 9 7 3 '17 1 , 910 3 10 ,, 18 A.M. 2*202 10 '23 0 22 20 8 ,l8 6 44 W.N.W. ,, I~A.M.1 10*/21 0 ;2210 2 11 20 417 5 49 W.S.W. .. 20A.M. 0 8*I21 0 '21 8 3 '21 3 18 0 W.

;; 25p.~.j 4 5 117 0 12 7 17 11 $1710 ~ 9 11, 3 6 ~ 0 10 12 8,

TABLE7.-RIVEB THAMES.HIQE WATER and LOW WATER, &c.-continued.

Ft. Ins. Ft. IndFt. Ina. Ft. 1ns.I FtIns FE Ins Ft. In3. Ft. Ins. Ft. In1 1874 11 l . .I ' .l May 3 AM. 0 4 20 6 ~20 2 40l1 0 45/52*4 34 ,, 4 A.M. Level 19 8 19 8 41 ,, 5 A.M. 0 419 719 3 50 1 813 4 ,, 11 P.M. 3 1 118 0 14 11 21 0 5*' 2 6 ,, 17a.~. 0 10*21 4 22 2 44 11*5 5 June ~A.M. 0 4 '19 4 l19 0 3 10 0535 ,, 4a.m. 0 5 19 8 '19 3 38 0731 ,, 9 P.M. 2 7 18 4'15 9 6 117 9 l1 8 36 0 7*4 1 ,, 16~.m. 0 5*19 6 19 11 4 0 20 9 16 9 45 13 32 ,, 23 P.M. 3 9 1710 '14 1 7 6 117 7 10 1 39 0 3*4 0 July 8 P.M. 2 0 18 4 '16 4 5 6 '17 3 11 9 36 11*4 7 ,, 15 A.M. 0 1*19 4 119 5 4 3 119 4 15 1 44Level 4 4 ,, 24 P.M. 3 3 17 0 113 9 7 2 ;l7 6 10 4 3 11 06 35 ,, 31 A.Y. 0 7* 19 2 3 16 10 3 10 0634 7 120 3 120 1 Aug. 1A.M. 0 3*20 4 20 7 3 4 ,l9 7 16 3 37 0 9*4 4 ,, 6 P.M. 0 11 18 4 117 5 4 3 ,l6 8 12 5 34 18*5 0 ,, 7 P.M. 3 2 19 7 16 5 6 6 118 11 12 5 34 0 8*4 0 ,, 29 A.M. 1 1*20 4 121 5 2 9 :l9 8 16 11 3 10 0 8*4 6 ,, 30 A.M. 1 1*20 0 ,21 1 3 0 20 0 17 0 41Level 4 1 ,, 31 A.M. 0 11*21 9 l22 8 3 5 21 4 17 11 44 0 5*4 9 Sept. 6 P.M. 2 018016 0 6 1i16810 7 41 ,, 11 AM. 0 11 '19 9 118 10 3 11 '1910 15 11 30 ,, 12A.M. 0 3 1910 '19 7 3 4 '19 10 16 6 31 ,, 13A.M. 1 1*19 4 20 5 4 3 '19 4 15 1 54Level 5 4 N. ,, 20 P.M. 4 3151011 7 7 5 16 3 810 32 05 29 ,, 28 A.M. 1 8*20 7 22 3 2 5 19 11 17 6 41 0 8*4 9 S.W. Oct. 4 P.M. 2 9 16 4 13 7 5 2 1511 10 9 25 0 5* 2 10 ,, 11 A.M. Level 19 10 19 10 3 7 18 8 15 1 37 12*4 9 ,, 26a.m. 2 2* 19 8 2110 1 2 118 7 17 5 34 11*4 5 S.S.W. ~,27 AM. 1 S* 20 10 22 6 2 1 819 8 17 7 39 1 2* 4 11 S.S.W. ,, 28 A.M. 2 1*20 0 22 1 1 7 118 11 17 4 38 11*4 9 E.N.E. Nov. 2 P.M. 3 6 17 10 114 4 6 10'17 4 10 6 34 ,, 10 A.M. 0 11 '20 0 19 1 4 2 l19 3 15 1 33 ,, 18 P.M. 3 6 h9 4 15 10 6 8 118 4 11 8 32 ,, 25 A.M. 0 6*'20 11 '21 5 3 8 '20 3 16 7 42 S.S.E. Dec. 1 PM. 0 7l17116 6 4 2 16 3 12 1 37 ,, 2 P.M. 2 418416 0 5 9/17 511 8 35 ,, 9A.M. 1819017 4 4 917 612 9 31 ,, 10A.M. 1 4'1810 20 2 3 0 118 0 15 0 44 0 10*' 5 2 N. W. ,, 18 P.M. 2 3 20 2 17 11 6 4 117 8 11 4 41 2 6*' 6 7 ,, 24 A.M. 0 4*20 0 20 4 5 3 ~199 14 6 57 0 3* 5 10 S. ,, 25 A.M. 0 6*20 4 20 10 3 8 i19 9 16 1 ' 42 0 7*4 9 N.W. ,, 31 P.M. 3 9 ,l9 7 15 10 7 3 18 9 11 6 36 0 10. 4 4 I1 l l 8 7 5 3 7 ! 0 3 3 4 'l 8 19 8 16 0 4 5 0 4* 4 9 S.S.W.

10 ,l8 6 11 8 5 4 0 2* 5 6

TABLE RIVER THAMES.HIGH WATER and Low WATER, &c.--conti~ztked. - -

Differ- Differ- Differ- mce at ence at ence of - H. W. L. W. Range. __ - 't. Ins. Ft. Ins./ Ft. Ins 't. Ins Ft. Ins Ft. Ins

3 2 '20 G 174 45 08 39 N.E. 7 11 1510 7 11 36 0 4' 310 2 7 119 6 l6 11 38 1 4' 50 N.W. 4 219415 2 47 0 3' 4 10 3 7 20 6 16 11 49 04 45 W.N.W. 6 3 16 9 '10 6 32 0 94 3 I1 5 917611 9 37 0 10' 45 2 3 18 1016 7 31 0 10' 3 11 E.N.E. 2 10 19 9 16 11 45 0 5* 410 E.N.E. S 8 19 G '10 10 37 0 1' 38 0 2 18 5!8 3 3 11 06 35 l 8 3 185 ,l0 2 58 07 51 0 3 19 81 .. 49 .. .. 2 11 03 28 40 02 3 10

29 0 13 2 10 47 03 44 S.E. 79 118 '103 6 27 15 12 Gale (?) I! W.S.W. 3 2119 0 ,l5 10 26 1 08 36

3 6i .. .. 51 ...... 20 1 .. .. 0 5' .. l - - -

m Yg::::: 2

l l; pW ..

* W0.1 m3

100

TABLEIO.-RIVER THAMES. HIGH TIDES ABOVE TRJXITYSTAXDArXI at BLACKWALLand LONDONDocm . Ft. Ins. 31st October.2 1827 ...... 11 21st November. 1827 ...... 3 2 2nd November. 1833 ...... 3 0 29thJanuary. 1854 ...... 3 7 2nd May. 1836 ...... 3 3 18th October. 1841 ...... 3 8 12th December.1845 ...... 3 P 24th January. 1850 ...... 3 4 12th November. 1852 ...... 3 7 15thFebruary. 1854 ...... 3 5 22nd December. 1863 ...... 3 6 24th November. 1866 ...... 3 4 8th February.1868 ...... 3 0 ~VESTUINYTBR. 1st March. 1869 ...... 3 4 Ft . Ins. 20thMarch. 1874 ...... 4 0 44 15th November. 1875 ...... 4 6 40 2nd January. 1877 ...... 4 0 41 31st January. 1877 ...... 3 7

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