66 PROCEEDINGS OF THE AMERICAN ACADEMY 



presented, and will confirm the views above stated, I will now 

 proceed to give details of the elementary analyses, and of the ex- 

 periments to determine such of the physical properties of the indi- 

 vidual bodies as are usually relied upon to identify or characterize 

 bodies of this class. I would here state, however, once for all, 

 that, unless specially mentioned, no one of the bodies operated 

 upon had received any chemical treatment except that of boiling 

 with sodium. 



Of the Analyses and Physical Properties of the different Bodies 

 separated from the Petroleum. 



1. Butyl Hydride and Butyl Iso-Hydride = C 4 H 10 .* 



My examination of butyl hydride and its isomeric associate in 

 the petroleum has been more limited than that of the other mem- 

 bers of the series to which they respectively belong. As these 

 bodies could at any time be readily obtained in larger quantity at 

 a manufactory, in the manner above described, I omitted to make 

 further use of the small quantities that I had incidentally col- 

 lected than to determine their boiling-points, and of one of them, 

 viz. iso-hydride of butyl, the specific gravity, which was found to 

 be 0.6107 at 0°. Ronalds has found the specific gravity of the 

 other, viz. hydride of butyl, to be 0.600 at 0°. 



In the original publication of the above tables, the boiling-point 

 of butyl hydride was given, with an interrogation point, as 0°; 

 for although I had observed that a mixture of the two bodies be- 

 gan to boil at about this temperature, it was on theoretical consid- 

 erations that this precise figure was given, and, of course, a more 

 positive statement would not be justifiable. That this, however, 

 is at least very nearly its true boiling-point, has since been con- 

 firmed by Ronalds, t who has made a special study of the most 

 volatile part of the petroleum, and who states that it begins to boil 

 at 0°. It does not appear, however, that he made a better separa- 

 tion of the two bodies, for he failed even to detect the presence 

 of butyl iso-hydride, and could not therefore have made an attempt 

 to separate it. Moreover, he worked by the old method. Ronalds, 

 however, collected a liquid boiling between 6° and 8° ; specific 

 gravity 0.6004, but did not regard it as a distinct body, but 



* Studied in 1868 by E. Lefebvre, Jahresb., 1868, p. 329. 

 t Journal of the Chemical Society, London, 1865. 



