Vlastimil Belohlavek The Meteorological Tradition Prague, Czechoslovakia ol Prague, Czechoslovakia Abstract This article is a summary of a public lecture given in 1975 on the 200th anniversary of the oldest meteorological ob- servatory in Central Europe—the Clementinum in Prague. A short history of the meteorological observations made at the Clementinum since 1775 and of the Meteorological Ser- vice in Prague are presented along with a description of the Clementinum. The newly awakened interest in long climatological ob- servation series makes it opportune to review the history of some of the old observatories. One of these is the Clementinum in Prague, where an uninterrupted series of observations has existed since 1775. Actually an interest in meteorology existed in Prague since the Renaissance. For most of its history in what was then Bohemia it was coupled to the pioneering efforts in astronomy. These originally centered at the Charles University founded in 1348 by Charles IV, Bo- hemian King and Roman Emperor. Its prominence in the astronomical world would have been secure forever by the association of Tycho Brahe (1546-1601) and Johannes Kepler (1571-1630) with the university. Both of them were also well known for their meteorological observations (Brahe, 1597; Kepler, 1605), although only Kepler appeared to have kept weather diaries while in Prague. The Prague observations were started by another astronomer, Joseph Stepling, at the Clementinum. This venerable building complex, in the heart of the Old Town of Prague, was built in the interval 1650-1756 by the Jesuits. It is a classical baroque group of buildings, com- prising three churches, a monastery, 32 houses, seven courts, and some gardens. It contains schools, an astro- nomical observatory, and a library. It is located on the FIG. 1. The historic tower of the Clementinum in Prague. right bank of the Vltava (Moldau)1 River and is a Prague of water and alcohol and hypsometric observations of landmark second only to the famed Hradschin Castle. The elevations. As a contemporary of Benjamin Franklin, he historic tower of the Clementinum is seen in Fig. 1. commented on lightning conductors. He speculated Upon removal of the Jesuit order in 1773 the Clemen- about the adaptation of plants to climate and the origin tinum became part of the university, which located its of precipitation. library there. Since 1935 it has also become the Czech For his meteorological observations he built a ther- National Library. Its collection of 2 million books and mometer of the Reaumur type. In contrast to many 5000 manuscripts places it among the world's great thermometers of this period, Stepling's model was ac- libraries. curate, as was shown by a calibration in 1829, long after Joseph Stepling, astronomer, mathematician, physi- his demise. His observations began in January 1752. The cist, and meteorologist, was born in 1716 in Regensburg, thermometer was hung outside a window oriented north. Germany. He studied at the Jesuit seminary in Olomouc Temperatures were read twice daily, at sunrise and sun- (Olmiitz) and in Prague. After ordination as a priest, set. Rainfall data were collected starting in February he devoted himself to studies in natural philosophy. He 1752. Barometric pressure was also read twice a day. constructed many of his own instruments. Among his Notes on cloudiness were also made. From the data many experiments were determinations of boiling points gathered, Stepling astutely reasoned that long years of 1 The names in parentheses are the translations of the observations were needed to cover the variations of the Czech names into German used on the old maps. weather at Prague. 1056 Vol. 58, No. 10, October 1977 Unauthenticated | Downloaded 09/27/21 10:44 PM UTC Bulletin American Meteorological Society 1057 FIG. 2. Annual temperatures observed at the Clementinum in Prague, 1776-1975 (courtesy of H. E. Landsberg). But from subsequent years, only fragmentary informa- the creation of the International Meteorological Organi- tion is available, especially after 1773 when the Jesuits zation (now the World Meteorological Organization, a had to relinquish their activities. Fortunately, in 1775 specialized agency of the United Nations). a student of Stepling, Anthony Strnad, became his suc- The Prague Clementinum observations continued with cessor as director of the astronomical and meteorological amazing regularity, unaffected by political changes. In observatory at the Clementinum. Since that time, ob- 1918 the weather service in the newly established Re- servations have been made daily, even during the two public of Czechoslovakia was taken over by the State world wars. It is now the longest uninterrupted series in Meteorological Service, which in 1954 metamorphosed Central Europe. It formed the backbone of a meteoro- into the Hydrometeorological Institute. The latter logical network in Bohemia, the first in the old Austro- gratifyingly continued three daily observations at the Hungarian Empire. The earliest stations in this network Clementinum. There, astronomical observations ceased were Zitenice, Plana, Gottersdorf, and Zatec. In 1780, in 1940. when J. J. Hemmer founded the first worldwide observ- As a bicentennial contribution the Hydrometeorologi- ing network of the Societas Meteorologica Palatina cal Institute (1976) has presented a gold mine of local (Rigby, 1973), Prague was one of the stations included. meteorological information in two impressive volumes. Strnad was succeeded in 1799 by the Rev. Martin They contain all daily observations from 1775 to 1975. Adam David as director of the meteorological and astro- These include barometric pressure; mean, maximum, and nomical observatory of the Clementinum. He had al- minimum temperatures; wind direction and force; and ready served as Strnad's assistant for a decade. David cloudiness and precipitation. After 1845, relative hu- also occupied the chair of astronomy at the University midity is also included. At the end of the second volume, of Prague and in 1816 served as rector of the university. some statistical summaries are given. A graph of the He also served as Secretary of the local Royal Society of mean annual temperature (Fig. 2) indicates no radical Sciences and supervised the meteorological stations spon- changes in the two centuries of observations. sored by that society. David retired in 1824. Among his successors were some very distinguished References meteorologists. Carl Kreil, director of the Prague ob- Brahe, T., 1582-97: Meteorologiske Dagbog, holdt paa Urani- servatory, made notable improvements in the design of borg for aarene. (See Collectanea Meteorologica, Kgl. recording meteorological instruments. C. Fritsch (1812- Danske Videnskabernes Selskab, Copenhagen, 1876, 263 79), who was born in Prague and associated with the ob- PPO servatory, wrote a learned treatise on the weather of Hydrometeorological Institute, 1976: Hydrometeorologicky Prague. He later became prominent in the newly formed Ustav Praha, Meteorologicka Pozorovani v Praze Kle- mentinu 1775, 2 vols., Prague, 459 pp. Central Agency for Meteorology and Geodynamics of Kepler, J., 1605: Prognosticum aufj das Jahr. (See, e.g., Fritsch, the Austro-Hungarian Empire in Vienna, where he was C. (Ed.), 1868: Joannis Kepleri astronomi opera omnia, responsible for the meteorological and phenological ob- Erlangen, Frankfurt.) servations. Another Prague alumnus, K. Jelinek (1822- Rigby, M., 1973: Ephemerides of the Meteorological Society 76), born in Brno (Briinn), became director of the of the Palatinate. Environ. Data Serv., NOAA, Washington, Central Agency in Vienna and acquired great merit in D.C., pp. 11-16. • Unauthenticated | Downloaded 09/27/21 10:44 PM UTC.