0(J4? Dilatation of the gases. 



even be proper to cut them out of the fame tube of glafs and 

 to make them of equal heights, fo as to render all the circum- 

 ftances as fimilar as poffible. 

 The tubes with Into one of thefe tubes I put atmofpheric air to the 100th 

 ^ h u e id t s w ° c e r ^ ft,c divifion, for example, and in the other the gas on which the 

 heated in a experiment was to be madelikewife up to the 100th divifion. 

 ftove ' 100 equal meafures of thefe gafes were thus fubmitted to ex- 



periment. I then carried the apparatus into a ftove, the tem- 

 perature of which I regulated at pleafure, and I obferved the 

 courfe of the dilatation of the gafes. Whatever attention I 

 paid to the obfervation I never could perceive any difference, 

 and I always remarked that the fame divitions were palled 

 through in the fame time. 

 The gafes were The gafes thus examined were never dire&ly received in the 

 P u . ri (^ d f am * i tubes; but they previoufly remained fome time in an interme- 

 were tried. diate veflel into which I introduced fome defiecative body, 



muriate of lime for example, and I then pafTed them into the 

 tubes, compreffing them with mercury, .which I poured by 

 means of a tube of fafety adapted to the intermediate veflel. 

 If (hefe general precautions be neglected the dilatation will 

 almofl always be too great; becaufe the influence of undif- 

 folved water will not be guarded againft, or of fome other 

 body capable of eafily taking the gafeous form. 

 Carbonic acid One hundred meafures of carbonic acid gas obtained from 



£ as > marble by means of fulphuric acid, were compared with the 



like portion of atmofpheric air. From the 5th to the 90th 

 degree (Reaumur) the expanfions were the fame, 

 and muriatic One hundred meafures of muriatic acid gas obtained by 



acid gas j means of concentrated fulphuric acid fro,m muriate of foda 



(very dry) being compared with 100 meafures of atmofpheric 

 air from the 3d to the S6th degree, the expanfions of the gafes 

 were found to be abfolutely the fame. This experimei0t, as 

 well as the preceding, were repeated feveral times, and the 

 fame refults were always obtained, 

 and fulphureous Sulphureous acid gas and nitrous gas undergo the fame di- 

 and nitrous gafes l a tation by the action of heat as atmofpheric air. 

 thTfamfas at- Doctor Prieftley, and Citizen: Guyton and Duvernois, found 

 mofpheric air. that ammoniacal gas dilated very coniiderably. With a view 

 to» C and Duver- to difcover the caufe that could have induced them to draw 

 nois found am- this conclufion from their experiments, I introduced (without. 

 SpTndmore preparation) into one of my tubes ammoniacal gas, obtained 



from 



