92 SULPHURETTED HYDROGEN. 



ingly disagreeable smell which it possesses. It is to 

 the presence of this gas the nauseous, disgusting smell 

 of putrefying animal matter is due. Sulphuretted 

 hydrogen is very poisonous, and it would probably 

 cause many fatal accidents, were it not that its of- 

 fensive odor warns us of its presence, and induces 

 us to take measures to disperse it by ventilation and 

 other means. 



183. Sulphuretted hydrogen is soluble in water to 

 a considerable extent, and the solution possesses the 

 strong and nauseous smell of the gas itself. The gas 

 is inflammable, and in burning produces water, and 

 sulphurous acid gas. Sulphuretted hydrogen has 

 sometimes been called an acid, for it possesses feeble 

 acid powers, combining with some bases and to a 

 certain extent neutralizing them. 



184. Sulphur has a strong affinity for most metallic 

 substances forming a numerous series of compounds, 

 which are called sulphurets : many metallic ores 

 are sulphurets, and in the process by which the 

 metals are obtained, the first operation consists in 

 roasting the ores, or exposing them to a dull red heat, 

 when the sulphur, being a volatile substance, is grad- 

 ually driven off. 



185. Chlorine is an element which is never found 

 free, but only in combination with some other element; 

 it is a very poisonous gas, causing very great irritation 

 when breathed, even though it is largely mixed with 

 air ; it is transparent, has a bright-yellow color, and 

 is remarkable for possessing in a very great degree 



