lo On the transmission 



A phial which had contained aqua regia faturated with 

 gold having a very pungent fmell, 1 examined the air 

 vs'ithin it, and found it to be of the ftandard of 1.65, 

 much worfe than common air. 



Air which had been confined with mujk was a little 

 worfe than common air. There was no fixed air in it. 

 Air confined in a fimilar phial, and with a fimilar cork, 

 about the fame time was not woife than common air, nor 

 w^as air confined with camphor. 



Water in which liver of fulphur was diflTolved did not 

 give out air worfe than before. 



6. Of the proportion of latent heat in fome kinds of air. 



That heat is neceffary to the aerial form of fubftances 

 is as evident as that it is neceflary to form the vapour 

 of water. I took the following method to afcertain the 

 proportional quantity of latent heat in thofe kinds of 

 air which are readily abforbed by water, expe£ting"to 

 find a confiderable difference between them, but I did 

 not find any. 1 inclofed the bulb of a mercurial thermo- 

 meter in one end of a glafs tube, and made the place air- 

 tight with a cork and cement ; then filling the tube with 

 mercury, I introduced a certain quantity of water, which, 

 fiirrounding the bulb of the thermometer, would foon 

 impart to it whatever heat it received by the abforption 

 of the air that was thrown up into it. 



The quantity of water in all the experiments was 44 

 grains, and the jar of air that 1 threw up into it held 

 nearly two ounce meafures. The kinds of air on which I 

 made the experiment were marine acid air, vitriolic acid 

 air, and alkaline air. In all the cafes the abforption of 

 the air raifed the thermometer four degrees of Fahren- 

 heit, which was a fpace of an inch and a half; fo 

 that a fmall difference w^ould eafily Iiave been perceived. 

 The vitriolic acid air required a, little agitation, and on 



this 



