482 Dr. Dalton's Observations on certain Liquids 



common air. By two careful trials, I found by the above 

 process the specific gravity of the vapour from the highest 

 rectified caoutchouc liquor to be 2-07, common air being 1, 

 and no allowance being made for aqueous vapour in a tempe- 

 rature between 60° and 70°. By another experiment the spe- 

 cific gravity of the vapour came out nearly 2. 



Another advantage is possessed by this vapour which others 

 have not, namely, that when a given weight or measure of the 

 liquor is passed through water, we are enabled to ascertain how 

 much of it is actually converted into vapour. Thus, to 60 

 cubic inches of common air I added 25 measures of the liquor, 

 •680 specific gravity : 



in 4 minutes the air and vapour became 70 inches 



7 76 ■ 



27 80 



and then remained stationary. 



Now, by calculating the weight of the 20 inches of vapour, 

 and comparing it with the weight of the 25 measures of liquor, 

 we find the ratio nearly as 3 to 4; so that only three fourths of 

 this highly rectified liquor is vaporized in such circumstances, 

 and the rest forms a delicate and partial smearing of oil over 

 the surface of the water. This shows that a higher degree of 

 rectification of the liquor is attainable. 



These four liquors, as might be expected, are all very com- 

 bustible; a lighted taper presented to them ignites them in- 

 stantly. They all burn with a white flame and great smoke. 

 No. 4 leaves no residue ; the others leave traces of carbon 

 and moisture. The smallest electric spark lights Nos. 4 

 and 3. 



The vapour also is highly inflammable, and when mixed 

 with oxygen gas may be exploded in Volta's eudiometer. A 

 mixture containing 1 measure of vapour requires 6 of oxygen, 

 and produces 4 measures of carbonic acid; it would appear 

 therefore to be constituted of 2 atoms of olefiant gas combined, 

 and possessing the space of 1 atom of said gas nearly. 



Chlorine gas acts upon the vapour much the same as on 

 olefiant. In one instance they seemed to combine in equal 

 volumes, but in another more chlorine was taken up. I did 

 not pursue this inquiry. 



Chloride of lime solution seems to have no effect upon the 

 vapour. 



Though the vapour is not absorbed by water in an eminent 

 degree, yet I find that water takes up one eighth of its volume 

 of the vapour, which is the same proportion as olefiant gas and 

 phosphuretted hydrogen are absorbed. It may be expelled 



