CHEMICAL SCIENCE. 1S3 



blood, which they modify, and thereby determine secondarily the 

 phenomena of insensibility. This agrees with the opinion of 

 M. Flourens, who stated long ago that in ordinary asphyxia the 

 nervous system loses its power under the action of black blood (blood 

 deprived of its oxygen); but in etherization the nervous system loses 

 its power, at first, by the direct action of the single agent which deter- 

 mined it. — Comptcs Rendus. 



ON PETROL. 



Bussenius and Eisensttick have investigated a rock oil, which is 

 obtained from some lias strata, near Hanover. The crude oil is 

 distilled with high-pressure steam, and the oil which distils over is 

 treated with sulphuric acid, which removes from it a peculiar bitu- 

 minous smell. Thus purified, it comes into commerce ; but the oil 

 for this investigation Bussenius and Eisensttick took as it distils over 

 with the steam, dried it, and submitted it to fractional distillation, 

 and found it to be composed mostly of hydrocarbons, including a 

 new hydrocarbon, which the authors named Petrol, but which they 

 were not able to separate directly ; but when the oil was treated 

 with a mixture of sulphuric and nitric acids, a crystalline nitre-com- 

 pound of this body was produced ; the other hydrocarbons, of which 

 the oil is mostly composed, are not altered, even by prolonged 

 contact with this acid moisture. This nitro- compound was purified 

 by repeated crystallizations from alcohol. The analysis of the substance 

 showed it to be not quite pure, but probably to contain some of the 

 nitro- compound of a higher hydrocarbon. 



Petrol has the same composition as xylole (Cahours, Church), but, 

 judging from the nature of its derivatives, it does not appear to be 

 identical with it. — Philos. Mag. 



COMBUSTION OP WET FUEL. 



Professor Silliman has read to the American Association a 

 paper, showing not only how the Combustion of Wet Fuel is possible, 

 but also how it may be accomplished with economical results. A 

 furnace invented by a Mr. Thompson, in 1854, arrests the escaping 

 products of combustion, and brings them back to consume them- 

 selves. This method shuts off the atmospheric air, and obtains 

 the requisite oxygen from the steam. 



GUN-COTTON. 



A correspondent writing to the Amerimn Journal of Photo- 

 graphy makes the following statement in reference to the spontaneous 

 combustion of Gun-cotton: — "While at work in my room, a spon- 

 taneous combustion of more than two ounces of gun-cotton took 

 place in my trunk, with a loud report, filling the contents of the 

 trunk with fire and smoke, which would have been destructive, had 

 no one been present. I purchased the cotton some three months 

 previous, and made good collodion from it, but laid it by to use 

 another sample. About two weeks before the explosion I acci- 

 dentally observed the bottle to contain a yellow vapour ; and on 



