2f56 DILATATION OF THE GASE3. 



The vapor of In order to determine the expanfion of the vapor of ether 

 in the tube- in * employed the two tubes I have already mentioned, atmof- 

 comparifon withpheric air being always the ftandard of comparifon. This ap- 

 atao p . air. p ara t us having been kept fome time in a ftove whofe tempe- 

 rature was about 60°, I introduced ethereal vapor into one of 

 the tubes, and into the other atmofpheric air, fo that they 

 each correfponded to the fame divifion. I then elevated the 

 They expanded temperature of the ftove from 60° to 100°, and I had the fa- 

 €oand ioo* tisfaclion to find, that whether the temperature was railed or 

 Reaumur, lowered, the ether and the atmofpheric air always corre- 



fponded at the fame time to the fame divifions. This experi- 

 ment, at which Citizen Berthollet was prefent, was repeated 

 feveral times, and I never could obferve any difference in the 

 When near its dilatation compared with that of atmofpheric air. I remarked, 

 ethere S al P vapor C h° wever > tnat at f° me degrees above the point of the ebulli- 

 •was condenfed tion of ether, its condenfations were a little more rapid than 

 rather more. thofe of atmofpheric air. This is owing to a phenomenon 

 which a great number of bodies prefent in paffing from the 

 liquid to the folid ftate, but which does not prefent itfelf a 

 few degrees above that of this period. 



The conclufion This experiment, by proving that the vapor of ether and 



may therefore be _ ~T" ,, „ , ,. 



extended tova- the gales dilate equally, thews us that this property in no re- 



pors i fpeft depends on the peculiar nature of gafes and vapors, but 



only on their elaftic ftate, and we muft confequcntly conclude 

 that all gafes and vapors dilate equally at the fame degrees of 

 heat. 



The vapors .will Since all the gafes are equally dilatable by heat and equally 



be more com- compreilible, fgas condenfable) and as thefe two properties 

 preflible near x , » « ! u ir i 



their point of depend on one another, as I ina.ll prove eltewhere, vapors 

 denfe flu dity orb e j n g equally dilatable with the gafes, ought alio to be equally 

 ique a .on. con jpreflible : but I muft obferve that this latter conclufion 

 cannot be true, unlefs while the comprefted vapors perfectly 

 retain the elaftic ftate ; which requires that their temperature 

 be Efficiently elevated to enable them to refift the premire 

 which tends to make them aflame the liquid ftate. 

 That dry and j h ave aflerted on the authority of Saufiure, and my own 



2ikc— Qu .V experiments confirm it, that very dry air, and air holding 

 more or lefs of water in folution are equally dilatable ; con- 

 sequently I am authorized from the whole of the facts to draw 

 the following conclufions. 



III. All 



