344 BI-SULPHURETTED HYDROGEN. 



decomposed, by being passed through an ignited porcelain tube, or 

 over ignited charcoal. Thenard. 



(r.) Alkalies absorb it readily, and thus it is easily separated from 

 common hydrogen. 



(s.) Potassium and sodium, heated in this gas burn brilliantly ; 

 i. e. much heat and light are evolved, and a sulphuret of the metal 

 is formed, while as much hydrogen gas is produced as the metal 

 would have liberated from water. Diluted muriatic acid produces 

 from the sulphuret the original quantity of sulphuretted hydrogen gas. 



5. COMPOSITION. According to Dr. Thomson, it is composed of 

 1 volume of the vapor of sulphur =1 proportion 1.111, +1 vol. of 

 hydrogen gas, 0.069 ; these numbers being almost exactly in the 

 ratio of 1 : 16, give the equivalent weight of sulphur very nearly 

 the same as that deduced from the composition of sulphuric acid.* 



6. LIQUEFACTION OF SULPHURETTED HYDROGEN. 



(a.) Mr. Faraday, by disengaging this gas in a recurved tube, 

 sealed, before the materials were brought into contact, the end oppo- 

 site to that in which they were contained being kept cold by a freez- 

 ing mixture, succeeded in condensing it into a liquid. 



(b.) It was limpid, colorless, and more fluid than ether ; equally 

 fluid at as at 45 Fahr. and its refractive power greater than that 

 of water. 



(c.) The tube being opened under water, the fluid rushed instant- 

 ly into gas, which was sulphuretted hydrogen. The pressure of its 

 vapor, at 50 of Fahr.f was equal to seventeen atmospheres, or 255 

 Ib. to the square inch. 



Remarks. Sulphuretted hydrogen gas exists abundantly in the 

 sewers and privies of great cities. I have observed, in London, that 

 a sudden and heavy rain would force it out in great quantities, taint- 

 ing the atmosphere, and tarnished white lead paint. In great cities, 

 especially in Paris, it is often fatal to those who clear away the filth 

 of the sewers : the best antidote and remedy is chlorine, especially 

 in the form of chloride of lime. 



BI-SULPHURETTED HYDROGEN. 



1. DISCOVERY. By Scheele originally, and afterwards examined 

 by Berthollet. J 



2. PREPARATION. Boil flowers of sulphur with liquid potassa ; 

 pour this reddish brown solution, by little and little, into muriatic acid ; 

 very little sulphuretted hydrogen escapes, and a part of it combines 

 with more sulphur, and precipitates, of an oily appearance ; or, fill 

 one third of a vial with muriatic acid, of the sp. gr. 1.07, and pour 



* Henry, Vol. I. p. 446, 10th Ed. f Phil. Trans. 1823, p. 192. 



* Ann. de Chim. XXV, and Phil. Trans. 



