114 Proceedings of the British Association. 



were made during the years 1841 and 1842, on every day except 

 Sundays, Christmas-day, and Good Friday, at intervals of every two 

 hours. Since 1842 they have been made at intervals of an hour. 

 For the purpose of rendering this communication more interesting, 

 Col. Sabine had compared these Toronto observations with those 

 made by M. Kairl, at the Observatory at Prague, in Bohemia. Col. 

 Sabine entered into a comparative description of those two stations, 

 both situate at a distance from the ocean between 300 and 400 

 miles in the middle of large continents. But there is one important 

 difference, that in Europe we enjoy a climate of higher mean temper- 

 ature, in proportion to the latitude, than they have in America, or 

 the isothermal lines descend lower in America than in Europe. Thus 

 the latitude and elevation above the sea of Toronto and Prague 

 stand thus: — 



Latitude. Elevation. 



Toronto.... 43° 39' 330 feet. 



Prague 50° 05' 582 „ 



Difference ...6° 26' 252 feet. 



Prague should be colder on account of its elevation, 0°'8 Fah. 



Mean Temperature of Toronto 44<M 1 Differerice 4 °- 3 . 

 Prague, 48°* 7 J 



Difference of Temperature corrected 1 Prague warmer 

 for difference of Elevation J 5°'l. 



Prague being 5°"1 warmer than Toronto, although its latitude is 

 6° 26' higher. Col. Sabine then drew attention to a table of the 

 diurnal oscillation of temperature, and explained it. The very small 

 differences in the results at the several hours of the two years, were 

 remarkable, as showing that we have already determined the diurnal 

 march of the temperature, as far as it can be obtained by two-hours 

 observations, with a close approximation to the truth. It also ap- 

 peared, that the climate of Toronto is warmer during the hours of 

 the day, and colder during those of the night, than that of Prague. 

 Another diagram exhibited the mean monthly and annual temperature 

 in each of the two years, compared with Prague, and a mean tempe- 

 rature of twenty years. He then exhibited a diagram showing the 

 elastic force or tension of the vapour in the atmosphere of those two 

 places, and the degree of humidity produced by it together with 



