in vacuo and in Gases. 



These tables, in which I have only inserted the greatest ten- 

 sions observed at given temperatures, show that the elastic force 

 of vapour of aether in the air is constantly less than that obtained 

 in vacuo ; the difference becomes greater in the same proportion 

 as the elastic forces themselves. 



Fearing that in the preceding experiments the tube by which 

 a communication was established between the balloon and the 

 manometer might be too small to allow of the necessary diffusion 

 of the vapour, I replaced it by one of the same diameter as 

 the manoinetric tube itself, that is to say, 22 millims. Under 

 these conditions the following series of experiments was made. 

 A small quantity of the liquid was always distilled over into the 

 manometric tube before the commencement of the observations. 



