MOLECULAR CONSTITUTION OF THE VOLATILE ORGANIC BASES. 
125 
Oa examining more closely the formulae of the preceding conspectus, we find that 
several of them represent basic compounds previously known. Chemists are ac- 
quainted with the beautiful reaction by which Zinin first linked aniline to benzole 
through nitrobenzole. 
C12H5NO4 
Benzole. Nitrobenzole. Aniline. 
Researches performed in the most different departments of organic chemistry have 
gradually elicited a series of carbohydrides differing from benzole by n C 2 Hg, and 
each of these terms, when treated with nitric acid, and subsequently exposed to the 
action of reducing agents, has yielded its corresponding base. We are now in the 
possession of the following series of alkaloids derived from hydrocarbons : — 
Aniline C 12 N 
Benzole C 12 Hg 
'U ^8 — ^\2 1^6 + 
C2 H2 
Tolu ole C 
Xylole C 
Cumole C 
Cymole C 20 ^u —^12 ^6-1-4 Cg H 2 
16 — ^12 ^2 f^2 
18 Hi2 = Ci 2 Hg + S Cg Hg 
C\4H9 N=Ci2H7N-f CgHg 
C 16 N=Ci 2 H; N-t-2 Cg Hg 
Toluidine 
Xylidine* 
Cumidine-f' C^g H 43 N=C \2 Hy N-1-,3 Cg Hg 
Cymidine:}: Cgg H^g N=C 4 g H 7 N-1-4 Cg Hg 
On comparing the formulae of the bases contained in the last table with those re- 
presenting the alkaloids derived from aniline by the introduction of methyl and ethyl, 
we find that they exactly coincide. Toluidine has the same composition as methyl- 
aniline ; xylidine, cumidine and cymidine are represented by the same formulae as 
ethylaniline, methylethylaniline and diethylaniline. The question then arises, are 
these substances identical, or are they only isomeric with each other ? I have care- 
fully compared the properties of toluidine with those of methylaniline, and also 
methylethylaniline with cumidine. These substances are not identical, but only iso- 
meric. The most striking dissimilarity we observe in the characters of toluidine and 
methylaniline. The former is a beautiful crystalline compound, boiling at 198°, 
yielding difficultly soluble, perfectly stable salts with almost all acids, and a splendid 
orange-yellow platinum-salt, which may be boiled without decomposition. We are 
unacquainted with any process by which we could convert this body into aniline. 
Methylaniline, on the other hand, is an oily liquid, boiling at 192°, whose salts are 
distinguished by their solubility and by the facility with which they are decomposed, 
aniline being reproduced {vide p. 113). The platinum-salt, even when freshly preci- 
pitated, is of a pale-yellow colour, which immediately darkens, turning perfectly 
black after the lapse of an hour. Scarcely less striking is the dissimilarity of cumi- 
dine and methylethylaniline, although in this case both substances are liquids. For 
* Unpublished researches of M. Cahoues. This chemist has lately found the long- wanted carbohydride 
Cjs Hjo, among the products of the distillation of wood. It comports itself exactly like benzole and its con- 
geners, yielding nitroxylole and xylidine. 
f On Cumidine, a new Organic Base, by E. Chambers Nicholson, Chem. Soc. Quart. Journ. i. 1. 
J This compound has been partly investigated by Mr. Noad. 
