[ 443 ] 



dided, and as I think, very rcafonably, by D'Amontons, Lambert, 

 and lately in an excellent memoire of Monge in the 5th vol. of 

 ; the Annaks de Chemie. 



By the experiments of general Roy, and thofe of Prieur Duver- 

 nois, I Ann. Chemie, the expanfions of air are various at various 

 degrees of heat. See Philof. Tranfadions, 1777. The general 

 alfo afTerts, that air under a preffure of 30 inches of mercury, or 

 only of 25 inches, undergoes fimilar expanfions, p. 708. 



Rejecting manometers, as I think they fhould be rejeded, it 

 appears to me that there are three tefts by which the fuitablenefs 

 of any coefficient fhould be tried. The firft is conformity with 

 the weight found at 32''. The fecond is the weight of the fame 

 volume of air at different temperatures, found by accurate weigh- 

 ing ; and the third is the agreement of barometrical menfuration 

 calculated according to the given coefficient, with the geometrical 

 menfuration. 



Note — The difference betwixt 32** degrees and any degree 

 above or below it I fliall call in the fequel the fundamental 

 diffe-Yence. 



Examination' 



