DILATATION OF THE GASES. Q($?) 



from the decomposition of muriate of ammonia by common than common 

 lime, and in the other tube an equal volume of atmofpheric air * 

 air. The ammoniacal gas dilated progreffively more than thebecaufe water 

 atmofpheric air in proportion to the elevation of temperature ,• ammon i aCa j f a j t 

 fo much fo that its volume was foon double that of the atmof-were prefent. 

 pheric air, but on obferving the furface of the mercury, and 

 the fides of the tube after the temperature was lowered, I 

 remarked fome traces of a liquid and fome cryftalline fpecks, 

 which could be nothing but muriate or carbonate of ammonia, 

 and it all difappeared when the temperature was fufficiently 

 elevated. I performed this experiment again by fufFering the 

 ammoniacal gas to remain fome time in an intermediate vefTel 

 containing cauftic potafh, and then its dilatations from to 95° 

 exactly followed that of the atmofpheric air. In this experi- 

 ment I obferved the furface of the mercury and the fides of 

 the tubes when the temperature had returned to 0, but I could 

 not perceive any indication of liquid, or any cryftalline fpeck. 

 This experiment was repeated feveral times, and always with 

 the fame event. 



Hence it may be feen that not only a liquid, but another Water is not 

 body capable of taking the gafeous ftate, may render the ex- t * lcrefore the 

 penment liable to error. Thele caules ought therefore to be er ror. 

 avoided with themofl fcrupulous attention. 



The experiments which I have juft related, and were all Hencet he d 'ffe- 

 made with great care, inconteftibly prove that atmofpheric air,^"* afe^don^ 

 oxigen, hidrogen, azote, nitrous, ammoniacal, muriatic acid, affea their ex- 

 fulphureous acid, and carbonic acid gafes expand equally by panfion by lieat * 

 the fame degrees of heat ; and that, consequently, their greater 

 or lefs denfity under the fame preflure, and at the fame tem- 

 perature, their more or lefs coniiderable folubility in water, 

 and their particular nature, in no refpeel influence their dila- 

 tation. 



I therefore conclude that gafes in general, provided they be 

 all placed in the fame circumftances, dilate equally with equal 

 degrees of heat. 



Thefe experiments on the dilatation of gafes naturally led Vapors, 

 me to examine that of vapors ; but fufpecting from the preced- 

 ing remits that they dilated like tiie gafes, I determined to 

 make experiments on one vapor only, and I chofe in prefer- 

 ence that of fulphuric ether, as being the moit eafy to manage. 



In 



