Knowledge. 



With which is incorporated Hardwiclce's Science Gossip, and the Ilhistrated Scientific News. 



A Monthly Record of Science. 



Conducted b\- W'llficd Mark Webb, F.L.S., and E. S. Grew, M.A. 



UCTULJKR, 1911. 



THE METEOROLOGY OF THE UPPER AIR.* 



By J. EDMLND CLARK. 11. A., B.Sc, F.G.S., F.R.Met.Suc. 

 [Bciii^ the Prcsidciitujl Address, 1911. to the Croydon Xatural History ctnd Scientific Society.] 



\\'HEN last year I addressed m_\- felldw nu-nibers. 

 who have honoured me by placing me in the chair, 

 which I am now vacating for one' who has long 

 given us able service, reference was made to the 

 three chief forward strides made in the realm of 

 Science during the opening decade of this twentieth 

 century. These are familiar to us as Mendelism. 

 Radiolog}- (if that word may be applied to express 

 the idea briefly), and the exploration of the Upper 

 Air. The first of these was then enlarged upon : 

 the second does not, perhaps, come so entirely into 

 the purview of our usual acti\'ities : and it is the 

 more appropriate that, as a worker in our second 

 section of Meteorology, I should turn to the subject 

 of the Upper Air. just as a consideration of 

 Mendelism linked itselt with our hrst Section — the 

 Botanical. This subject, moreover, claims an added 

 interest in view of the remarkable progress made 

 in the last two years in practical flight by man. 



Although few definite generalised results had 

 been reached previous to the present century for 

 heights much exceeding one mile (two kilometres), 

 pioneer work of no small value dates back to the 

 early sixties. For moderate heights the first begin- 

 ning was made one hundred and fift\' vears before. 

 The astronomer. Professor Alexander Wilson, of 



Glasgow, and one of his students, in 174'), attached 

 thermometers to kites strung in series. This was 

 three years earlier than Franklin's classic experi- 

 lueiit. by which he pro\ed that lightning was an 

 electric discharge. 



From that day on, kites ha\e been one of the chief 

 methods for the investigation of the free air in its 

 lower parts, second in importance onl\- to the results 

 in higher parts b\- balloons. Loftv mountain stations 

 have also afforded many valuable facts. But it is 

 obvious that records so obtained are vicioush- 

 affected in a double manner, so far as the real state 

 of the free air is concerned, nameh', by the 

 disturbing effects of the land surface, with its own 

 conditions of temperature and moisture, and bv the 

 dislocation, through the slopes, of the normal 

 atmospheric flow, resulting in profound modifications 

 of temperature and saturation. 



For practical purposes onl\- one other source of 

 knowledge remains, that afforded b}' clouds as to 

 wind direction, saturation, and whether the stratum 

 is above or below the freezing-point. The first 

 scientific work through clouds began with their 

 classification by Luke Howard, in 1803, which, after 

 remaining practical!}- unaltered for nearh- a centiir\ . 

 has now been re-organised rather than replaced. 



Autliorities. — Besides the frequent communications during the last few years to the Royal Meteorological Society, and in 

 Symons's Monthly Meteorological Magazine, the writer has specially consulted the \aluable summary of our ]<novvledge 

 presented by Messrs. Gold and Harwood to the Winnipeg Meeting of the British .Association in 1909; Sir John Moore's 

 " Meteorology, Practical and Applied" (1910) ; Meteorological Office Publication No. 202 (Perturbations of the Stratosphere) ; 

 "Das Werter": and Mr. William Marriott's account of James Glaisher's Meteorological Work (19041. There is a 

 very informing article by Professor .\. Lawrence Rotch, the able director of the Blue Hill Observatory, near Boston, U.S.A., 



in Tlie Scientific .American of October 22nd. 1910. 



I William Whitaker, F.R.S., F.G.S. 



373 



