AOT) COMPOSITION IN OEOANIC COMPOUNDS. 
271 
The ethers which arise from the combination of these bodies with acids C„ O^, 
exhibit on the other hand boiling-points rising with the increasing number of carbon- 
atoms. And this remark applies not only to those ethers of the glycols which contain 
two molecules of an acid-radical (compare Table XX.), but also to those in which only 
one of the two basic hydrogen equivalents of ethyl-glycol is replaced by an acid-radical. 
Table XXIII. 
Cs Hg 0 , 
^12 ^12 ^6 
CUH 44 O, 
Monoacetate of Ethyl-glycol 
Monobutyrate of Ethyl-glycol 
Monovalerate of Ethyl-glycol 
Atkinson, 182°. 
Louren^o, about 220 °. 
Louren<^o, about 240°. 
One more example of a compound exhibiting a boiling-point lower than that of its 
lower homologue is offered by the cyanurates of methyl and ethyl. According to Wuetz’s 
earlier experiments, cyanurate of methyl, CijHgNaOg, boils at 295 ° ; according to a later 
obser\'ation, at 274 °; cyanurate of ethyl, CigHuNgOg, according to the earlier observa- 
tion, at 276 °; according to the later, at 253 °. The boiling-points of the cyanic ethers, 
on the other hand, rise with the increase of the number of carbon-atoms ; cyanate of 
methyl, C4 H3 N O2 (boiling-point 40 °, W uetz), and cyanate of ethyl, Cg H5 N O2 (boiling- 
point 60 °, WuETz), exhibit the difference of boiling-points usual in this kind of ethers. 
Isomeric compounds belonging to the same type, and possessing the same chemical 
character, have the same boiling-point. This seems to follow from the boiling-points, 
such as have been observed for isomeric ethers €„ !!„ O4 (Table IV.); for ethers €„ Hn-s O4 
and C„Hn_io04 (Table VII.); and for so-called simple and mixed radicals CnHn+2 
(Table XIV. ). Boiling-points, which at any rate very nearly approach each other, have 
also been observ'ed for the isomeric ethers €„ O2 (see Table XVI.). For the isomeric 
ethers C„ II„_2 Og, observation has hitherto yielded boiling-points which sometimes agree, 
sometimes differ. As yet no sufficient grounds exist for attributing different boiling- 
points to isomeric compounds of the same type and the same chemical character. It 
may sometimes be difficult experimentally to prove the identity of the boiling-point of 
two such compounds as an ethyl-ether and the isomeric methyl-compound. The methyl- 
compounds have in general so great a tendency to boil irregularly, and at temperatures 
anomalously raised, that quiet ebullition permitting the observation of the correct boil- 
ing-point is often scarcely to be attained. 
Isomeric compounds belonging to the same type, but possessing a different chemical 
character, have different boiling-points. This is evident, e. g., from a comparison of 
the acids and ethers C„ H„ O4 (Tables III. and IV.) ; of the acids and ethers C„ Hn_2 O4, 
CnH„_8 04, or CnH„_,o04 (Tables VI. and VII.); of the alcohols and ethers CnH„+2 02 
(Tables II. and XVI.) ; of the mercaptans and the sulphur-compounds isomeric with 
them C„ H„+2 S2 (Table XVIII.). 
Isomeric compounds belonging to different types have different boiling-points. Allyl- 
