Lieut.-Col. Sabine's Report on the Meteorology of Toronto. 1 1 3 



The mean monthly values of the vapour pressure, and of the gaseous press- 

 ure at Greenwich exhibit also the same correspondence with the variation of 

 the temperature in the different months of the year as at Toronto. 



Synopsis of the Annual Variation of the Temperature, Vapour pressure, and 

 Gaseous pressure at Greenwich. 



It appears therefore that the annual and diurnal variations derived from 

 the observations at Greenwich present a most satisfactory accordance with 

 those at Toronto in those points which were brought most prominently be- 

 fore the Association at York, and to which the attention of the Section was 

 especially called, viz. — 



First, in regard to the diurnal variation : 



1 . The vapour tension and the force of the wind have each a minimum, 

 and the gaseous pressure a maximum, at or near the coldest hour of the day. 



2. The vapour tension and the force of the wind have each a maximum, 

 and the gaseous pressure a minimum, at or near the warmest hour of the 

 day. 



3. The diurnal march of each from the minimum to the maximum, and 

 from the maximum to the minimum again, is continuous, like that of the tem- 

 perature, without any interruption deserving of the name. 



4. At Greenwich as well as at Toronto the diurnal variations of the vapour 

 tension and of the gaseous pressure, produce by their combination the double 



