1916] on Illusions of the Upper Air 605- 



weather have really more to do with typography than with meteoro- 

 logy. Gradually the use of isobars introduced by Leverrier came in ; 

 they and their reproduction by lithography have now become universal^ 

 and the weather maps of all countries use a common form with only 

 slight variations in detail. 



The Study of Cyclones and Anticyclones. 



In 1866, a year after Fitz Roy's death, when my present story 

 begins, the Kew party had made good its claim, and the Royal Society 

 had undertaken by means of the new Meteorological Office to establish 

 seven other Observatories in various parts of the country just like 

 the one at Richmond, and to use the automatic records in explana- 

 tion of the weather as set out in the daily maps. The explanation 

 of the winds and the interest of the sailor were still the justification 

 of the pubUc expenditure. 



Meteorologists knew about cyclones from Piddington in 1848, 

 and about anticyclones from Galton in 1863 ; and from that time 

 onwards until the end of the century the study of cyclones and anti- 

 cyclones was the dominant idea of dynamical meteorology. 



It was mainly conducted by observations at the earth's surface, 

 and necessarily so. In 1852 Welsh, the superintendent of Kew 

 Observatory, had made four sets of excellent observations of the 

 upper air in balloons, and Olaisher had followed them up by a large 

 number of ascents for the British Association, which reached their 

 climax in the famous ascent with Coxwell in 1862. They added a 

 good deal to our knowledge but very little to our ideas. They told 

 us that the atmosphere showed continual decrease of temperature 

 with height, and that surprised nobody ; it was a natural incident in 

 the gradual transition from the temperature of the surface of the 

 earth to the absolute zero of space. " The nicely calculated less or 

 more" was not of vital importance. Cyclones and anticyclones 

 obviously belonged to the upper air, the regions where clouds are 

 formed and dissipated, where rain and snow and hail are produced, 

 but balloon ascents told us little about them beyond confirming the 

 surmise that there are great ascending currents associated with certain 

 forms of cloud. 



The only real information to be got about the atmosphere in 

 upper regions was that contained in observations of pressure at the 

 surface, which is the cumulative result of the whole thickness of the 

 atmosphere, and the amount of rain, hail or snow which was noted 

 as falling from above. There were also observations of the forms of 

 cloud and their motion, and, if we please, of their position. The rest 

 is necessarily speculation, so that out of these observations meteoro- 

 logists were obliged to imagine for themselves what cyclones and 

 anticyclones are, how far up they extend, how they are produced 

 and maintained, what kind of air they are made of, and so on. 



