Intelligence and Miscellaneous Articles, 427 



therefore failed. It is to be observed that mercury is the only metal 

 which has thus the power of disturbing the analysis by the humid 

 way. — Ann. de Chim. et de Phys., tome lviii. p. 218. 



ANALYSIS OF PYROXYLIC SPIRIT. — METHYLENE. 



MM. Dumas and Peligot state that pyroxylic spirit was discovered 

 by Mr. Philip Taylor in 1812, and that he published an account of it 

 in 1822 j and they also admit that Mr. Taylor's observations with 

 respect to its properties are perfectly correct, and that they have pro- 

 cured pyroxylic spirit possessing all the properties which he assigns 

 to it. 



MM. Dumas and Peligot, in common with most chemists who 

 have within a few years analysed any carburetted hydrogen or any 

 substance containing carbon and hydrogen, have found a new com- 

 pound of these elements, or rather, to use their own phrase, " nous 

 donnerons le nom methylene a un radical dont il est impossible d'eviter 

 la supposition." Formerly it was deemed to be sufficiently early to 

 name a substance when it had actually been found, but now a name 

 is given on the supposition that it must exist. This radical the authors 

 say is a carburetted hydrogen, which is the most simple of all, and is 

 stated to consist of a volume of each of its elements, giving as its 

 composition 



4 atoms of carbon 153*05 or 85*95 



4 atoms of hydrogen ...... 25 '00 — 1 405 



J atom m&hylene 17805 100*00 



The authors then remark that methylene, bicarburetted hydrogen, and 

 Mr. Faraday's carburet of hydrogen are three isomeric * bodies, in 

 which the number of the elementary atoms go on doubling, the first 

 C H, the second O H 2 , the third C 4 H 4 . Pyroxylic spirit yielded by 

 analysis, 



4 atoms carbon 153*05 or 37*97 



8 atoms hydrogen 50*00 — 12*40 



2 atoms oxygen 200*00 — 49 63 



403*05 10000 



It is represented as a bihydrate of methylene, or 



1 atom methylene 178*05 or 44*17 



2 atoms water 22500 — 55*83 



403*05 100 00 

 Pyroxylic spirit when kept in a badly stopped bottle undergoes no 

 change by contact of the air ; but when its vapour and atmo- 

 spheric air and spongy platina are exposed together, much heat is 

 evolved, and formic acid is produced • while alcohol in the same 

 circumstances produces acetic acid. During this action the pyroxylie 

 spirit loses all its hydrogen, oxygen replacing it, so that the bihydrate 



* In the commencement of the paper pyroxylic spirit is stated to be iso- 

 morp/ious with alcohol * is not this a misprint for isomeric? 



312 



