582 FOURTH REPORT — 1834. 



which consists of the same proportions of carbon, nitrogen, 

 and oxygen as cyanic acid. It is wrong, thei*efore, to speak 

 of the fulminic as a second cyanic acid, and useless to couple 

 them together as isomeric bodies. Tartaric and racemic acids 

 are of the same ultimate composition, but they certainly con- 

 tain different radicals, and probably have as little natural i-ela- 

 tion to each other as any two vegetable acids which could be 

 named. Why, then, associate them as isomeric bodies, and call 

 them the tartaric and paratartaric acids? 



4. A minute trace of adventitious matter may sometimes affect 

 the properties of a chemical body to a surprising degree. 



Professor fiose, of Berlin, has shown that the two kinds of 

 phosphuretted hydrogen, one of which is spontaneously inflam- 

 mable in air, and the other not so, are of the same composition 

 and specific gravity. To account for their possessing different 

 properties, recourse is had to the doctrine of isomerism. But 

 my observations indicate the existence of a peculiar principle 

 in the spontaneously inflammable species, which principle may 

 be withdrawn, and leaves the gas not spontaneously inflamma- 

 ble. Phosphuretted hydrogen gas, which is not spontaneously 

 inflammable in air, may be made so, by the additiontoit of one 

 ten-thousandth part of its volume of nitrous acid vapour. There 

 are grounds for supposing that the peculiar principle of the 

 ordinary gas is a volatile oxide of phosphorus analogous to 

 nitrous acid, and that it is present in a minute, almost infinite- 

 simal, proportion. Subsequently to the meeting of the Associa- 

 tion, an account of the author's researches on phosphuretted 

 hydrogen has been published in the number for Dec. 1834, of 

 the London and Edinburgh Journal of Science. 



On some new Chemical products obtained in the Gas-tuorks 

 of the Metropolis. By George Lowe, F.G.S., M.R.I., 

 M. Art. Soc, Engineer to the Chartered Gas Company. 



Mr. Lowe stated that in consequence of the recommendations 

 adopted at the last meeting of the Association, he was induced 

 to lay before the Section some specimens of the products of 

 heat, obtained at the Metropolitan Gas-works. He exhibited a 

 fine specimen of artificial pyrites, containing cubical and octa- 

 hedral crystals. 



These are produced by a long-continued action of fire, at a 

 dull red heat, and are deposited on the aluminous interior coat- 

 ing of the cast iron pots, in which muriate of ammonia is sub- 

 limed into the sal ammoniac cakes of commerce. 



The rough muriate contains also some sulphate of ammonia, 

 and the clay soon becomes saturated with muriate of iron. 



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