261 



PROCEEDINGS 



ROYAL SOCIETY OF EDINBURGH. 



VOL. III. 



1854-5. No. 45. 



Seventy-Second Session. 

 Monday, Ath December 1854. 

 Right Rev. Bishop TERROT, V.P., in the Chair. 

 The following Communications were read : — 



1. Farther Experiments and Remarks on the Measurement 

 of Heights by the Boiling Point of Water. By Professor 

 J. D. Forbes. 



This paper is in continuation of one printed in vol. xv. of the 

 Royal Society's Transactions. The object of it is to test the cor- 

 rectness of the method of observation, and of calculating the re- 

 sults, there proposed ; and to compare both with those of more recent 

 authors, particularly of M. Regnault of Paris, and of Dr Joseph 

 Hooker. 



The author finds the results of his subsequent observations in 1846 

 in the Alps, up to heights considerably above 10,000 feet, to agree 

 well with those previously published, made in 1842. They combine 

 in showinof a sensibly uniform fall of the boiling point at the rate of 

 1° for 543 feet of ascent,* which differs only 6 feet (in defect) 

 from his previous determination. The average deviation of the in- 



* In a standard atmosphere at 32' of ter ipcrature. 

 VOL. III. Y 



