[ 37^ ] 



Thus the temperature of the fummit of Arthur's feat, near 

 Edinburgh, though only 684 feet above the bafe of Hawk-hill 

 obfervatory, was, on the 31ft of January, 1776, found to be 6*^ 

 warmer than the temperature below. Phil. Tranf. 1777, p. 777 

 and 728. At about eleven o'clock in the forenoon, M. De Luc 

 tells u?, that in winter he fometicies found the temperature on 

 the fummits of mountains from 2500 to 3000 feet high, exadlly 

 the fame as that of the plains. Modif. § 203. A circumftance 

 that never occurs in fummer. Count Fraula, in the 3d volume 

 of the Memoirs of Bruffels, has fhewn by experiments, that thaws 

 begin above and are gradually propagated downwards ; Meffier, 

 in the Memoirs of Paris. 1776, p. 19, having placed two ther- 

 mometers, one at 20 feet above the ground and another 54. feet 

 higher, obferved this latter to fland conftantly fome degrees 

 higher than the former, and in one inftancc fix degrees, on the 

 firfl: day of February, 1776, though the weather was ferene and 

 the wind at ea(l, when thefe obfervations were taken. Ibid. p. 16. 

 The cold below has been attributed to the froft tiiat flill remained 

 unthawed ; but granting that its influence cou'.d reach to the 

 height of 20 feet, the queflion is, whence proceeded the change 

 in the temperature of the upper atmofphere, which fome fliort 

 time before was much colder? It evidently did not proceed from 

 the earth, as it conflantly does in fummer. 



The 



