[stupart] PRESIDENTIAL ADDRESS 3 



These records present some particularly interesting features as 

 the results lie between those obtained in Northern Europe and in 

 the equatorial regions. 



The general form of the annual curve shewing the height of the 

 stratosphere in Canada, is fairly in accord with that of Northern 

 Europe, it being lower in winter than in summer and autumn, but 

 the range is larger. Then the curves showing the annual variation 

 in temperature differ quite widely, the lowest temperature occurring 

 in Europe during the winter and in Canada during the summer. 

 The mean temperature of the statosphere over Toronto is several 

 degrees lower than in Europe. These results point to latitude as a 

 factor as the stratosphere over the Equator is at a higher altitude 

 and some 30° colder than in middle latitudes. A temperature of 

 -133° Fah. was obtained from an instrument sent up from Batavia 

 on Nov. 5th, 1913. 



Observation has shown that the most stable barometric condi- 

 tions on the surface of the Globe are those of the sub-tropical belts 

 of high pressure over the oceans, in both hemispheres, which while 

 they wax and wane and also change their position with the sun's dec- 

 lination, are fairly persistent throughout the year, and together with a 

 belt of relatively low pressure around the Globe in the equatorial 

 regions are closely associated with the trade winds on both sides of 

 the equator. It is generally allowed that these belts of high are largely 

 the outcome of the overflow from the hot expanding atmosphere of 

 the equatorial regions, and perhaps it is not an unlawful assumption 

 that the primary distribution of atmospheric pressure is a belt of rel- 

 atively low pressure around the Globe in the equatorial regions or 

 more properly near the thermal equator; a belt of high between lati- 

 tudes 30 and 40 in both hemispheres and then a lessening pressure 

 towards higher latitudes and the poles. 



Impressed on this primary system is another which is clearly the 

 outcome of the large range in temperature between winter and summer 

 over continental areas and the comparatively equable temperature 

 of the oceans. Over Asia and eastern Europe during the winter the 

 weather becomes very cold and contraction in the lower strata of the 

 atmosphere leads to a lowering of the barometric surfaces, a conse- 

 quent increasing flow of air in the upper regions from the tropics 

 to higher latitudes intensifying the normal high pressure belt and 

 causing an extension of marked anticyclonic conditions into the cen- 

 tral and more northern portions of both Asia and Europe. 



In summer the converse obtains and the heating up of the con- 

 tinent leads to expansion of the overlying air and the thermal equator 

 is transferred to southern Asia, and the sub-tropical belt of high dis- 



