2 THE ROYAL SOCIETY OF CANADA 



European centres. The result has been a common system of observa- 

 tion over the whole globe, and fruitful discussions of Meteorological 

 phenomena, which in their varying form are manifested over the 

 entire earth. 



Following the systematizing of observations at ground level, a 

 system for the exploration of the atmosphere by kite and balloon 

 has been gradually taken up by the various countries until I believe 

 it is now a fact that all the civilized countries are doing something 

 to assist in the work. The necessity of obtaining upper air data was 

 recognised very many years ago by Glaisher and others who made 

 many balloon ascents for purely scientific purposes, but probably 

 the two men who have done the most were M. Teisserencde Bort of 

 France and Lawrence Rotch of the Blue Hill Observatory near Bos- 

 ton, the former being especially identified with the inauguration of 

 the system of unmanned balloons carrying registering instruments 

 and the latter of the kites, also carrying instruments. 



There is now an International aeronautical Committee, which 

 arranges the dates and times at which balloons are to be sent up and 

 attends to the publication of results which are thus made available to 

 all engaged in meteorological investigation. 



Canada first took part in the Upper Air work in February, 

 1911 — since when 78 balloons have been despatched and 44 have been 

 returned with records of pressure and temperature. 



The following are some of the facts: 



1. Only three balloons have been found west of the point of depar- 



ture, and these instances occurred during a period of fine weather 

 and high barometer at midsummer; the great majority travelled 

 in directions between EN.E. and SE. 



2. The height reached by the balloons in winter is not as great as 



in summer, this average being as 12: 15. 



3. The isothermal layer or stratosphere is at a lower level in winter 



than in summer, the average height being 10.1 kilometres in 

 winter and 13.4 in summer. 



4. The stratosphere has a lower temperature in summer than in 

 winter — the average of 11 flights in summer showing-62°-3 

 and 12 flights in winter showing -59 C. 



5. The stratosphere is found to be warmest when the balloon flight is 



in the same direction as a strong surface wind. 



6. Somewhat meagre data seems to indicate that the stratosphere 



is coldest when the surface pressure is nearly uniform over a 

 large area. 



7. The longest balloon flights have been just prior to the develop- 



ment of great storms and the flights have been nearly in the direc- 

 tion of the subsequent storm movement. 



