68 RegnauWs Researches upon the Dilatation of Gases. 



that it remains the same under all pressures. But the variations 

 of the barometer in the same place are too small to permit us to 

 come to so general a conclusion ; it serves to prove only that 

 very small variations of pressure have no sensible effect in chang- 

 ing the coefficient of the dilatation of air." 



The results of the experiments of Regnault upon air under 

 different pressures are — 



" The preceding experiments demonstrate that the law admit- 

 ted by philosophers, that is to say, that the air dilates the same 

 fraction of its volume whatsoever its density, is not exact. The 

 dilatation of air between the same limits of temperature increases 

 as the density of the gas becomes greater, or in other terms, as 

 its molecules approach one another." 



The same is shown to be true for carbonic acid. 



Conclusions. — " My experiments do not confirm the two fun- 

 damental laws of the theory of gases, admitted up to the present 

 time by all philosophers, viz. 



" 1. All gases dilate equally between the same limits of tem- 

 perature. 



" 2. The dilatation of the same gas between the same limits 

 of temperature is independent of its primitive density. 



"Ought these laws now to be abolished? I do not think 

 so. I believe that these laws, as well as all those that belong to 

 the gases, such as the law of volumes, &c, are true to a certain 



