M. Regnault on the Elastic Force of Vapours, 277 



the probable errors of observation, so that it can be reduced to 



the much simpler formula 



log £ = a 4- ha. 



This consideration, and the great resemblance which the graphic 



curves belonging to different substances bear to each other when 



F 

 logr^r- is taken for ordinates, lead me to think that the law of 



variation of the tensions of vapours with the temperatures would 

 appear under a very simple form by taking as an independent 

 variable, not the temperature such as we define it in a completely 

 arbitrary manner, but another element which would be in a direct 

 relation with the constitution of each body, and whose origin 

 would be fixed for each of them. 



The Tables of the elastic forces of the vapours of alcohol, 

 ether, chloroform, bisulphide of carbon, and essence of turpen- 

 tine have already appeared in this Journal. In the new Table 

 these tensions are determined for every 5 degrees; and there 

 are further determinations of the tensions of benzole, quadri- 

 chloride of carbon, C 2 CI 8 , of chloride, bromide, and iodide of 

 ethyle, of methylic alcohol, essence of lemon, acetone, and oxalic 

 ether. In the following Tables we shall give the tensions of 

 mercury vapour, and also of some liquefied gases. 



