1865.] of the Series C n U 2n+2 . 167 



had previously carefully studied the hydride of heptyl and its derivatives. 

 In the preparation of ethyl-amyl a considerable quantity of the radical 

 amyl is always formed, the behaviour of which with chlorine I also investi- 

 gated. The first results of these researches have been published in the 

 'Journal of the Chemical Society,' vol. i. (new ser.) p. 425. I obtained 

 the chlorides C 7 H ]5 Cl and C 10 H 21 Cl, which appeared to be identical with 

 the chlorides of heptyl and of decatyl. The next step was to ascertain how 

 the lower terms of the two series are acted upon by chlorine, and to study 

 closely the differences which were stated to exist between methyl and 

 hydride of ethyl. The results which I obtained were, however, quite dif- 

 ferent from those of former observers. I found that when equal volumes 

 of chlorine and of methyl, and equal volumes of chlorine and hydride of 

 ethyl, are exposed to the diffused daylight, the principal product of the 

 reaction consists in both cases of the compound C 2 H 5 Cl, a body having the 

 composition and characteristic properties of chloride of ethyl, and as neither 

 in the physical nor in the chemical properties of the two hydrocarbons a 

 difference is known to exist, I concluded that methyl and hydride of ethyl 

 are identical. It appeared very probable that the same relation might 

 exist in the case of the higher terms of the two series, which, however, 

 showed some differences in their physical properties, and I left it an open 

 question whether there is only one series of hydrocarbons, C n lH 2n+2 , or 

 whether two series exist which exhibit the characters of physical isomerism. 



The following communication contains the results of researches carried 

 out for the purpose of deciding the above question in the case of the hydro- 

 carbons ethyl-amyl and hydride of heptyl, and of amyl and hydride of 

 decatyl. The results of this investigation are in some respect not so com- 

 plete as I could desire. The chief difficulty in working upon this subject 

 is the very small yield of the alcohol of the series which is obtained from 

 a proportionally large quantity of the hydrocarbon, the alcohol being cer- 

 tainly that compound by the study of which and of its derivatives much 

 light would be thrown on many still obscure points. Only, in the most 

 favourable cases, one-third of the theoretical yield of the chloride is 

 obtained ; and in preparing the acetate from the chloride a large quantity 

 of the latter is decomposed into olefine and hydrochloric acid, and this 

 decomposition increases as the compounds become richer in carbon. Thus 

 a small fraction of the hydrocarbon is converted into the acetate ; and in 

 order to prepare from this ether the pure anhydrous alcohol, losses are 

 unavoidable, which diminish considerably the yield of a pure product. I 

 have tried in different ways to obtain other compound ethers from the 

 chloride, or to convert it into the iodide, without finding a better method 

 than that originally employed, to which therefore I finally returned. 



The specific gravities given in the following account are compared with 

 water at 4 C., or they give the weight of one cubic centimetre in grammes ; 

 the boiling-points are provided with the necessary correction for the 

 mercurial column above the vapour. 



