at Leith Fort every Hour of the Day in 1824 and 1825. 379 



I have given these examples principally with the view of 

 shewing the application of the results of the hourly register, and 

 not with the design of contrasting the hours employed by diffe- 

 rent observers ; for it yet remains to be determined how far the 

 form and dimensions of the daily curve, as determined for Leith, 

 are applicable to places in different latitudes, and situated 

 at different heights above the sea. At Paris, for example, the 

 mean temperature of the day occurs before 9 o'clock in the morn- 

 ing ; and at Tweedsmuir * in Scotland, 1 300 feet above the sea, 

 it happens before 7^ h A.M. ; but it must be remarked, that the ob- 

 servations at 9 o'clock in the one case, and at 7^ h in the other, 

 are compared with a calculated mean temperature, and not with 

 the mean temperature of the whole 24 hours j- . 



It is curious to remark, that, with the exception of the hours 

 of 10 A. M., and 10 p. M., no similar pair of hours has been used 

 by meteorologists. The following Table will shew how nearly 

 at Leith the mean of every similar pair of hours approaches to 

 the mean temperature of the day. 







* At Salem, Massachussets, where a very accurate register has been kept by Dr 

 Holyoke for twenty-six years, the morning mean temperature always occurs before 

 8 o'clock in the morning. 



f According to a very accurate register kept by Mr FAIHLIE, schoolmaster of 



this parish, the results for 1825 are, 



j;; 



Mean Temp, at Mean Temp, at Mean Temp, deduced 



74 k A. M. 8J 11 P. M. from these. 



45M67 4 









