ON THE THEORY OF TYPES 1N CHEMISTRY. 121 
hydrogen we have C,0,H, or anhydrous formic acid; the replace- 
ment of a second equivalent would yield C,O,H.,, or the unknown 
formic aldelyde; a third, C,O°H,, the oxide of methyle; anda 
fourth, C,H,, or formene. By substituting methyle for one or 
more atoms of hydrogen in the previous formula, we obtain those of 
the corresponding bodies of the vinic series, and it will be readily 
seen that by introducing the higher alcoholic radicals we may derive 
from C,0O, the formulas of all the alcoholic series. A grave ob- 
jection to this view is however found in the fact that while this 
compound may be made the type of the aldehydes, acetones, and 
hydrocarbons, it becomes necessary to assume the hypothetical 
C,0,, H®9, as the type of the acids and alcohols. Oxide of carbon, 
C,0., is according to Kolbe, to be received as the type of hydro- 
carbons like olefiant gas, (C,HMe,) while C,O, in which ethyle re- 
places oxygen, is C,H, or lipyle, the supposed triatomic base of 
glycerine. 
The monobasic organic acids are thus derived from one atom of 
C,0,, while the bibasie acids, like the succinic, are by Kolbe, 
deduced from a double molecule C,O,, and tribasic acids, like the 
citric, from a triple molecule C,0,,. He moreover compares sul- 
phuric acid to carbonic acid, and derives from it by substitution the 
various sulphuric organic compounds. Ammonia, arseniuretted and 
phosphuretted hydrogen, are regarded as so many types; and by an 
extension of his view of the replacement of oxygen by electro-posi- 
tive groups, the ethylids ZnEt, PbEt;, and Bikt,, are, by Kolbe, 
assimilated to the oxides of ZnO, PbO,, and BiO,. 
Ad. Wurtz, in the Repertoire de Chimie Pure for October, 1860, 
has given an analysis of Kolbe’s memoir, (to which, not having the 
original before me, I am indebted for the preceding sketch) and 
follows it by a judicious criticism. While Kolbe adopts as types a 
number of mineral species, including the oxides of carbon, of sulphur 
and the metals, Wurtz would maintain but three, hydrogen, (H,) 
water, (H,O.,) and ammonia, (NH,); and these three types, as he 
endeavoured to show in 1855, represent different degrees of conden- 
sation of matter. The molecule of bydrogen, H, (M,), corres. 
ponding to four volumes, combines with two volumes of oxygen (O,) 
to form four volumes of water, and may thus be regarded as condensed 
to one-half in its union with oxygen, and derived from a double mole- 
cule, M,M,. In like manner four volfimes of ammonia contain two 
