351 



XXVII. — Report on the Hourly Meteorological Register kept at Leith Fort in the 

 Years 1826 and 1827. By Sir David Brewster, K.H., D.C.L., F.R.S. 

 (Plates XXIV. and XXV.) 



(Bead 19tli February 1866.) 



Having already published in the Transactions* a detailed report on the 

 Hourly Meteorological Register kept at Leith Fort, at the expense of the Society, 

 during the years 1824 and 1825, it is unnecessary to enter into any recapitula- 

 tion respecting the origin and history of this class of observations. 



The singular and unexpected results obtained from these Registers, and the 

 rapid approximation to general laws which some of these results exhibited, 

 attached a great interest to the observations of future years ; and it is satisfac- 

 tory to find that the results for the two following years of 1826 and 1827 are 

 almost perfectly coincident with those for 1824 and 1825, not only in their 

 general relations, but even in their numerical laws. 



The following are the Mean Temperatures of the four years during which the 

 hourly observations were made at Leith Fort : — 



Mean Temperature of 1824, ...... 47588 



of 1825, 48-911 



of 1826, 48-436 



of 1827, . . . • . . 48-407 



Average Mean Temperature of four years, .... 48-335 



The following Tables contain the mean temperatures for every day of the 

 year, and for every hour of the day for 1826 and 1827: — 



* Vol. X. p. 362. 



VOL. XXIV. PART II. 5 C 



