186 [June 19* 



When I first made known the action of heated lime upon coal-gas, 

 chemists accounted for the phenomena observed by two assumptions : 

 I. That the sulphur-compound decomposed was free bisulphide of 

 carbon. II. That the decomposition was due to a reaction between 

 water and bisulphide according to the following equation : 



CS 2 + 2HO=2HS + CO 2 . 



It was easy to show that these assumptions were erroneous, but ex- 

 ceedingly difficult to demonstrate the truth. 



That the sulphur in gas does not usually exist as free bisulphide of 

 carbon is proved thus. 



Gas which has been purified at the gas-works by lime, and which 

 contains 20 or 30 grains of sulphur in 100 cubic feet, may be 

 passed for a considerable time through a tube containing cold slaked 

 lime without producing discoloration ; but if the same gas be charged 

 with a minute quantity of bisulphide-of-carbon vapour and passed 

 through the same lime-tube, the lime becomes yellow and green from 

 decomposition of the bisulphide of carbon. 



If instead of passing the gas through lime it be passed through 

 triethylphosphine, the beautiful red crystals which this base gives 

 with bisulphide of carbon are not formed ; but if the base be dissolved 

 in alcohol or ether, and the gas passed, through this solution, the red 

 crystals are formed, as Dr. Hofmann first proved. The alcohol or 

 ether dissolves out the bisulphide of carbon from the hydrocarbon 

 compounds of which it forms a part ; and when it is thus dissolved it 

 reacts with triethylphosphine. 



Naphthalin, benzole, and other fluid hydrocarbons condensed from 

 purified gas yield sulphide of hydrogen and other sulphuretted com- 

 pounds by simple distillation, yet these do not produce the well- 

 known red crystals with triethylphosphine. They may, moreover, be 

 digested for weeks in an alkaline solution of oxide of lead without 

 producing any sulphide of lead. Under similar treatment bisulphide 

 of carbon yields hydrosulphocarbonate and sulphide of lead in a few 

 hours. 



If the sulphuretted fluid hydrocarbons condensed from gas be 

 mixed with ammoniacal alcohol and heated, and an alcoholic solu- 

 tion of acetate of lead be then added, a black precipitate is formed 

 after some time, which evolves sulphide of hydrogen upon addition 

 of an acid. In this case neither hydrosulphocarbonate nor hydro- 



