NITROUS OXIDE. 479 



(k.) "An iron wire burns in this gas nearly as well as in oxygen 

 gas." 



7. COMPOSITION. 



(a.) The equivalent number of this gas has been already stated 

 to be 22. 



(b.) As two volumes of nitrous oxide require, for decomposition, 

 two volumes of hydrogen, which can saturate only one volume of 

 oxygen ; it follows that the residuary nitrogen, which is found to be 

 expanded into two volumes, was combined with 1 measure of oxygen, 

 and that the three were condensed into two ; or one volume of ni- 

 trogen combines with half a volume of oxygen, and the volume and 

 a half occupy one volume, as before stated under specific gravity ; 

 one volume of nitrogen, or 1 proportion, is 14, and half a volume of 

 oxygen is 8, and 8 + 14=22. 



(c.) Ammoniacal gas 100 measures -\-15Q nitrous oxide, produce 

 a combustible mixture ; the oxygen of the oxide uniting with the hy- 

 drogen of the ammonia. 



(d.) Olejiant gas burns, when mingled with this gas and ignited. 



(e.) Carbonic oxide 1 vol. -{-nitrous oxide 1 vol. fired by the elec- 

 tric spark, over mercury, produce 1 vol. carbonic acid, and 1 vol. of 

 nitrogen. 



This method of analysing nitrous oxide was introduced by Dr. 

 Henry.* 



Let 1 100 measures of nitrous oxide, proved, by agitation with 

 green sulphate of iron, to be free from nitric oxide, be fired with a 

 slight excess, say 110 or 115 measures of pure carbonic oxide, f and 

 100 measures of carbonic acid will be obtained. 



(f.) If this gas be electrized in a tube over mercury, it is partially 

 decomposed, being converted into nitrous acid, and common air, and 

 a similar effect is produced by passing it through a thoroughly ignited 

 porcelain tube, glazed within and without. 



8. CONDENSATION OF NITROUS OXIDE. 



(a.) Effected by Mr. Faraday,^ by means similar to those that have 

 been already described in the case of other gases. Some nitrate of 

 ammonia, rendered very dry, by a partial decomposition by heat, in 

 the air, was placed in the end of a recurved tube, sealed at both ex- 

 tremities ; the end containing the salt was then heated, while cold 

 was applied to the other end, by a mixture of ice and snow. 



(b.) Two fluids were obtained, the one water, with a little nitrous, 

 acid and oxide, and the other, floating upon it, being very mobile > 

 limpid, and colorless, was the liquified nitrous oxide. 



* Ann. of Phil. N. S. Vol. VII, p. 299. 



t Previously washed with a solution of caustic potash. 



t Phil. Trans. 1823, p. 195. 



