PHYSICAL PHENOMENA OF THE [JPPEE REGIONS OF THE 



ATMOSPHEBE. 1 



By Prof. Alfred Cornu, 



D. C. L., F. B. S.f Officer of the Legion of Honor, Vice-President of the Academy of 



Sciences, Paris. 



The primary and effective cause for almost all the physical phe- 

 nomena that occur in the earth's atmosphere is the heat of the sun. 

 The atmosphere may then be considered as an immense heating - appara- 

 tus that has for its fire the sun, for its boiler the earth or the clouds 

 heated by the solar rays, and for its condenser the radiation that occurs 

 toward interplanetary space. 



The means at the disposal of physicists and meteorologists for study- 

 ing the different regions of the atmosphere are very limited; they are 

 usually obliged to content themselves with very indirect observations 

 and to proceed by induction. Most interesting phenomena do indeed 

 occur iu the upper regions at almost inaccessible heights. The pur- 

 pose of this paper is to show by a few experiments that physical 

 meteorologists are beginning to attain a true explanation of natural 

 phenomena. You will see, indeed, that in certain cases they can not 

 only exactly produce those phenomena, but often they are able to effect 

 a true synthesis of them by using means in every way analogous to 

 those actually operative in nature. 



I will commence by enumerating the means in use among meteorolo- 

 gists for studying the different regions of the atmosphere. 



The most direct method is founded upon the use of the aerostat. 

 The aerostat, or balloon, allows us, in fact, to transport our meteorolog- 

 ical instruments into the very midst of the atmospheric strata we wish 

 to study. 



Unhappily this method is difficult, expensive, and even dangerous; 

 therefore it is employed only in exceptional cases. The aerostatic 

 ascensions most productive of results have been those of Gay-Lussac 

 (1804), of Glaisher (1862), and recently that of Dr. Berson of Stassfurt 

 (1894), who ascended more than 9,000 meters. 



1 Translated from the Proceedings of the Royal Institution of Great Britain, Vol. 

 XIV, pp. 638-648. 



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