ON THE METEOROLOGY OP TORONTO IN CANADA. 



45 



The nights being proportionally colder and the days warmer than at Prague, 

 the mean daily range of the thermometer is greater, being 9°'9 at Prague and 

 11°"35 at Toronto. The mean temperature of the 24 hours occurs earlier in 

 the forenoon and earlier in the afternoon at Toronto than at Prague. 



Annual Variation. — The next table exhibits the mean monthly temperatures 

 in each month of 1841 and 1842, and their average. In a separate column is 

 shown the amount by which the temperature in each month exceeds or falls 

 short of the mean temperature of the year. This forms the annual variation of 

 the temperature ; it is, as is well known, the consequence of the earth's annual 

 motion in its orbit, which regulates the order and succession of the seasons, and 

 occasions a progression of temperature from a minimum in the midwinter to a 

 maximum in the midsummer. This also is a single progression, having but 

 one ascending and one descending branch. The annual variation of the 

 temperature at Prague is placed by the side of that at Toronto, by which 

 means the eye is at once enabled to judge of the general agreement and the 

 minor differences; the latter are also shown more distinctly in the final 

 column. 



In viewing the minor differences shown in the last column, we must not 

 overlook that our numbers are based on two years only of observation, and 

 that for an annual progression, a single year forms in fact but a single ex- 

 periment. When we view the differences which some of the months present 

 in the columns representing the observations in 1841 and 1842, we shall readily 

 acknowledge that more than two years are required to give that approxima- 

 tion to a mean annual progression which the present state of science requires. 

 There are, however, some features of difference which present such obvious 

 characters of system that we may have reason to expect that the observations 

 of a greater number of years will but make them more assured. Thus the 

 spring months are all proportionally colder, and the summer months hotter, 

 at Toronto than at Prague. There is also one remarkable difference, viz. in 

 January, which is proportionally a colder month by above 4° at Prague than 

 at Toronto ; and from the magnitude of the amount, it wears the aspect of a 

 permanent climatological difference. Now it is well known that in the month 



