346 Sir D. Brewster on the Law of Daily Temperature. 



dinates we may deduce the mean temperature of the whole 

 year, that is to say, the mean of all the horary ordinates." 



The next important relation which we have deduced from 

 the hourly observations is, that which the mean temperature 

 of each hour bears to that of the whole year. The following 

 are the results obtained from four years' observations at Leith 

 and three at Inverness : — 



The value of the preceding table is very great. It enables 

 us in climates at least analogous to those of Leith and Inver- 

 ness, and approximative^ in others, to deduce the mean tem- 

 perature of the year, from meteorological registers containing 

 only a single daily observation. Thus, if the mean of all the 

 observations in a register kept at 6 h p.m. was 51 o, 000, then, 

 since the mean temperature of that hour exceeds the mean 

 temperature of the day by 1°'984, we shall have 51° — 1°*984. 

 = 49 o, 016 for the mean temperature of the place of observation. 

 In like manner, when in meteorological registers, as in most of 

 them, the observations have been made at two or three hours 

 which do not give the mean temperature of the day, we can 

 easily deduce from the preceding table the corrections which 

 are necessary to make them give the mean annual temperature 

 of the place of observation. 



If we wish to discover at what two hours, or at what three 

 hours, the observations should be made to discover the mean 

 temperature, we have only to find in the above table the hours 



