1865.] of the Series C n ll 2n+2 . 467 



0-1952 substance gave 0-6130 carbonic acid and 0-2510 water. 

 Calculated. Found. 



C T 84 85-7 85-65 



H u _1 14-3 14-28 



8 100-0 99-93 



The acetate also has the same pear-like smell as the acetate from ethyl- 

 amyl. It boils at 180-182, and has the specific gravity of 0*8605 at 16. 

 0-2446 substance gave 0-6135 carbonic acid and 0-2540 water. 

 Calculated. Found. 



C 9 108 68-35 68-40 



H ]8 18 11-39 11-53 



2 32 20-26 



158 100-00 



From the acetate the alcohol was prepared by heating with a concen- 

 trated solution of caustic potash. Dried over caustic baryta, the alcohol 

 boiled at 164-167. 



The specific gravity at 19-5 = 0'8286. 



Its odour cannot be distinguished from that of the alcohol from ethyl- 

 amyl. 



By oxidizing it with chromic acid, first the odour of cenanthol is per- 

 ceived, and then an oily acid is obtained, which by its smell, as well as 

 the analysis of its silver-salt, was recognized as cenanthylic acid. 



0-1205 of the silver-salt obtained by saturating the rectified acid distillate 

 with carbonate of silver, gave 0'0551 of metallic silver, or 45*72 per cent., 

 the formula C 7 H 13 AgO 2 requiring 45'57 per cent. Ag. 



The annexed Table gives the boiling-points and specific gravities of the 

 hydrocarbons C 7 H 1G of different origin, and their derivatives. From these 

 data, as well as from the experiments detailed in this and in my former 

 papers, it appears that we meet here with examples of absolute isomerism, 

 viz. compounds having the same percentage composition and the same con- 

 stitutional formula (A. Crum Brown), but differing from each other in 

 their physical properties. This is not only the case with the hydro- 

 carbons, but also, in a greater or less degree, with their derivatives. 



Ethyl-amyl and hydride of heptyl from azelaic acid, as well as the corre- 

 sponding chlorides, were obtained in as pure a state as possible, and in pretty 

 large quantities ; and although only small quantities of the acetate, alcohol, 

 and olefine from the hydride were at our disposition, yet the greatest care 

 was taken to obtain them pure, and all determination of the boiling-points 

 and specific gravities were carried out under the same circumstances, the 

 same thermometer always being used, so that they may be fairly compared 

 with each other. 



