148 



THE GEOLOGIST. 



C 10 H 12 hydride of amyl, boiling-point 34° C. 

 C 12 H 14 hydride of hexyl, „ 68° C. 



C 14 H 16 hydride of heptyl, „ 98° C. 



C 16 H 18 hydride of octyl, „ 119° C. 



In addition to these lie obtained a small quantity (about one gramme) of a 

 liquid boiling between 20° and 30° C, and hence we may infer that also hy- 

 dride of butyl is present in small quantities. 



The author stated in the paper above alluded to that hydride of amyl 

 boils at 39° C. The same compound from petroleum boils at 34° C. He 

 finds, however, that the presence of traces of foreign substances alter the 

 boiling-point of this body very considerably. Thus, for instance, he ob- 

 tained from the crude oil about one ounce of a liquid which boiled from 

 15° to 20° C. ; after treatment with nitric acid, the volume of the liquid re- 

 mained almost unchanged, showing that only a very small quantity of sub- 

 stance had been removed ; but, after drying with potash and rectifying 

 over sodium, it was found that a mere trace of the liquid boiled below 30° 

 C ; nearly the whole distilled at 34° C, and consisted of hydride of amyl. 

 Of the four hydrides which he isolated, he had only prepared the hy- 

 dride of heptyl in quantity ; four gallons of turpentine substitute boiling 

 between 80° and 150° C, yielded three pounds of the pure compound. 



In order to obtain from this other heptyl compounds, it was transformed 

 into the chloride according to the excellent method described by Hugo 

 Miiller,* which consists in the addition of a small quantity of iodine to 

 the substance which is to be treated with chlorine. The substitution oc- 

 curs much more rapidly in this case than when chlorine alone is employed, 

 and goes on in absence of the daylight, so that a rapid current of chlorine 

 gas can be led into the liquid without any chlorine escaping with the hy- 

 drochloric acid vapours. 



Hence it is seen that the constitution of American petroleum, at least 

 that portion boiling below 120° C, is quite analogous to that of the oil 

 from cannel tar. 



Petroleum consists mainly of the hydrides of the alcohol radicles, it 

 contains very small quantities of benzol and toluol, and probably traces 

 of olefines, whilst in the cannel coal oil the hydrides are found in 

 smaller quantities, and benzol and toluol in proportionally larger amounts. 

 In the oil obtained by di tillation of boghead coal, Greville Williams 

 has discovered a series of hydrocarbons possessing the composition and 

 physical characters of the hydrides Cn H rt +2> also benzol and its homo- 

 logues and olefines .f 



The rock oils obtained in other countries appear to posses a somewhat 

 similar constitution. 



Thus, for instance, Warren de la Hue and Hugo MullerJ found in the 

 Han goon tar, benzol, toluol, xylol, and cumol and hydrocarbons of the for- 

 mula Cn Hn+2. They were, however, unable to isolate from these a com- 

 pound of definite composition and boiling-point. The rock oil from Sehnde, 

 in Hanover, consists, according to the investigation of Busenius, Eisen- 

 stuck,§ and Uellsmann,|| of hydrocarbons of the same general formula, but 

 they likewise failed to obtain definite products. 



Pebal and JFreund** found in the rock oil from Gallicia benzol and homo- 

 logues, carbolic acid and homologues, and hydrocarbons which are not 

 attacked by the strongest acids, and probably identical with those previ- 

 ously mentioned. 



* .Tourn, Chem. Soc, 15, 41. f Phil. Trans. 1S57. % Jahresbericht, 9, 606. 

 § laebig's Aunalen, 113-115. |] lb. 114-279. ** lb. 115, 119. 



