CLIMATE. 



23 



Hour. 



Diff. of Temp. 



Hour. 



Diff. of Temp. 



1 A. M. 



— 2-133 



1 P. ic. 



+ 2-882 



2 — 



— 2-334 



2 — 



+ 3-203 



S — 



- 2-578 



3 — 



+ 3-265 



4 — 



— 2-818 



4 — 



+ 2-972 



5 — 



-2-873 



5 — 



+ 2-605 



6 — 



-2-613 



6 — 



+ 2-027 



7 — 



- 1-983 



7 — 



+ 1-277 



8 — 



- 1 -238 



8 — 



+ 0-375 



9 — 



-0-212 



9 — 



— 0-438 



10 — 



+ 0-745 



10 — 



-0-990 



11 — 



+ 1.683 



11 



— 1 -463 



12 — 



+ 2-510 



12 — 



- 1-868 



It appears from this table that the mean of the same 

 hours, morning and evening, taken together, comes within 

 a single degree of the mean of the whole twenty-four ; and 

 that 9 a.m. and 8 p.m. are nearest to the true mean, which 

 occurs about 9J a.m. and 8^ p.m. The mean minimum 

 is found at 5 a.m. ; the mean maximum at 2f p.m. But 

 these hours show only the several means for the whole year. 

 The mean of the twenty-four hours occurs in January at 

 10| a.m. and 7 p.m.; in July, at 9 a.m. and 8| p.m. 

 The minimum temperature in January is at 6 a.m., and 

 the maximum at 3 p.m.; in July they are at 4 a.m. and 

 5 p.m. The difference between the mean maximum and 

 mean minimum is in January little more than 2£ degrees, 

 while in July it exceeds 9g degrees. 



From these results it is evident that observations of the 

 temperature at stated hours cannot form exact com- 

 parisons with those taken from the mean of the daily 

 extremes, even on the whole year, and still less in summer. 

 In winter the mean at any hour must differ very little from 

 that of the whole twenty-four; since the mean extremes are 

 under 3 degrees. But selecting observations made in the 

 most suitable places, and applying the before-explained 

 correction to those at stated hours, we may arrive at 

 general conclusions with respect to the temperature of 

 Britain, not likely to err widely from truth. 



