44< Dr. T. Thomson on Pyroxylic Spirit and its Compounds. 



It boils by my trials at 150°. Dumas and Peligot state 

 the boiling point to be 151°'7*, under a pressure of 29*96 

 inches of mercury; Macair and Marcet, 150°t; vvhile Leo- 

 pold Gmelin makes it as low as 137°:j:; and Kane found it 

 140° §. 



The tension of its vapour at 5*70° is 3*27 inches of mer- 

 cury. The specific gravity of the liquid at 68° is 0'79S, So 

 that in this respect it does not differ much from alcohol. The 

 specific gravity of its vapour at the temperature of boiling 

 water is 1*120, that of air being unity. 



It was analyzed by MM. Dumas and Peligot, and by Mr. 

 Kane, of Dublin, who obtained 



ID.&P. Kane. 



Carbon I 37*22 

 Hydrogen 12*46 

 Oxygen 50*32 



1 atom = 0*75 or percent. 37*5 



2 atoms= 0*25 12*5 



1 atom = 1-00 50-0 



2*00 100 



We might consider it as a compound of 1 atom carbo- 

 hydrogen, and 1 atom water. But the analogy of aether ren- 

 ders it more likely that it is an oxide of dicarburetted hy- 

 drogen. 



Dumas and Peligot found the specific gravity of the vapour 

 of pyroxylic spirit to be 1*120, while Kane obtained 1*121, 

 or almost exactly the same result. 



Now, 1 volume carbon vapour weighs 0*4166 



2 volumes hydrogen gas weigh 0*1388 



^ volume oxygen gas weighs 0'5555 



l-lUl 

 Hence, it is obvious that the vapour consists of 1 volume car- 

 bon, 2 volumes hydrogen, and half a volume oxygen, con- 

 densed into 1 volume. 



* Ann.de Chim. ei de Phi/s.,Wni. 10. 



t Bibliotheqiie Universelle, xxiv. 126. 



X Handbuch der Theoret. Chimie, ii. 344. 



§ ^nn. der Pharmacie, xix. 165. 



II Liebig obtained Carbon 5420 



Hydrogen IMl 



Oxygen .3469 



100 



But the specific gravity was 0*804. The substance analyzed was different 

 from pyroxyh"c spirit. Liebig got it from L. Gmdin.— Ann. der P harm. 

 v, 32. 



