C. M. Warren on the Volatile Hydrocarbons. 217 
series, the corresponding difference of boiling-point is about 19° 
C.; hence, that the difference between the boiling-points of any 
two members of such a series is x .19° for a difference of C,H, 
in the elementary formule. In the earlier observations on this 
subject, this relation between the boiling-points and formule was 
found so nearly constant in the different series examined, that 
any deviations from this apparent general law were referred, not 
unreasonably, to assumed inaccuracies in the determination of 
the boiling-points of the bodies compared. But the more recent 
- : 
ence is greater, and others in which it is less, than ) 
elementary difference of C, H,. That there are such exceptional 
this subject, different theories have from time to time been 
advanced b Schréder, Léwig, Gerhardt, and others, and sup- 
Peculiar nature of the C,H, in each case. He regards organic 
Compounds for the most part made up of radicals, which he 
calls “ components,” of which he makes seven. Three of these 
earth compo 
(H,)-—* (H,)”—which was supposed to lower the boi 
* Annalen der Chemie und Pharmacie, 1855, xcvi, 2. a, 
* Poggendorff ’s Annalen, 1844, Ixii, 184,387. 
R. SCL—Seconp Serres, Vou. XL, No. 119.—Serr., 1865. 
