AGRICULTURAL CHEMISTRY. 4j 



cay, it" very often happens that an atom of the sulphur 

 combines with one of hydrogen, and forms this gas. 

 It may be recognized in the smell of rotten eggs, also 

 about the docks in cities, and frequently in sinks. 

 This gas is exceedingly unhealthy, as well as very op- 

 pressive, ^and it should never be tolerated about our 

 buildings. The matter which gathers about the out- 

 let of the sink should be frequently removed, or 

 should be so diluted with peat or loam, with the ad 

 dition of a little plaster or chloride of lime, as to give 

 off no offensive odor, as this sulphuretted hydrogen 

 is very apt to be generatedin such places, and to op- 

 erate injuriously on the health of families. 



Sulphuretted hydrogen is formed in well-manured 

 soils, and it is probably from this that plants obtain 

 in part' the sulphur, which they require in order per- 

 fectly to develop their seeds. It is a gas ; but it read- 

 ily dissolves in water ; in which form (that of a lim- 

 pid solution) it may enter the roots of plants. 



64. Carhuret of Hydrogen (CH' and Q'W) is of 

 two kinds. (See Table I., 18.) Light carburetted hy- 

 drogen is composed, as its symbol imports, of carbon 

 one atom, hydrogen two. This is the gas which often 

 forms bubbles on the surface of stagnant water. It is 

 inflammable. If you thrust down a pole into the bot- 

 tom of water in which vegetable matter is decaying, 

 bubbles will rise and float on the surface. These will 

 burn with a gentle explosion and a whitish flame, if a 

 torch be applied. This same gas is generated in richly 

 manured soils, and probably it has something to do 

 with furnishing plants with a small part of their food. 



