M. Boussingault on the Compositson of Bitumens. 79 



fracture conchoidal ; at a temperature of 800 it becomes soft 

 and elastic, and is decomposed before the blowpipe. It contains 

 Carbon, 0.753; Hydrogen, 0.099; Oxygen 0.148, a compo- 

 sition which is represented by the formulary C. ^ H. ^ O 6 . which 

 indicates that asphaltine is the result of the oxidation of pe- 

 troline. 



The bitumen of Bechelbronn, purified by ether, seems to be 

 nothing more than a mixture of petroline and asphaltine. It 

 contains Carbon, 0.870; Hydrogen, 0.112; Oxygen, 0.018. 



On the whole, then, it would appear that glutinous bitumens 

 are mixtures, probably in all proportions, of two substances, 

 which we can isolate, and which have each a definite composi- 

 tion. One of these principles is solid and fixed, and in its na- 

 ture approaches to asphalt ; the other liquid, oily, and volatile, 

 resembles petroleum in some of its properties. Hence we 

 may readily conceive how the consistence of bitumens varies 

 in a way we may call indefinite ; its degree of fluidity being 

 regulated by the relative proportion of the mixture of its in- 

 gredients. 



The analogy which exists between the asphaltine and the 

 asphaltum of mineralogists, led me, says the author, to inquire 

 if this analogy is maintained in their composition ; I have sub- 

 mitted the asphaltum of Coxitambo (Peru), which may be con- 

 sidered as the type of the species, to analysis. This asphaltum 

 has a fracture which is eminently conchoidal, with a high degree 

 of lustre. The weight is 1.68; it is decomposed before the 

 blowpipe, and when burned leaves 0.0016 residuum. It contains 

 Carbon, 0.750; Hydrogen, 0.095 ; Oxygen, 0.155. 



Memoir on the Chemical Composition of Asses'* Milk. By 

 M. E. PELIGOT.* 



THESE researches have been undertaken for the purpose of 

 ascertaining whether the changes which are produced by asses' 

 milk in the animal economy are owing to the differences in the 

 proportion of the constituent elements of this liquid ; and, sup- 



* Read to the Academic des Sciences of Paris. 



