CHAPTER III. 

 CARBON BISULPHIDE, CS3. 



5. Carbon Disulphide. — Preparation.— By projecting fragments 

 of sulphur on to red-hot coals. On the large scale, vertical cast-iron 

 cylinders huilt in masonry are used. They are filled with charcoal, 

 which is kindled. As soon as it has reached a sufficient heat, the 

 sulphur is introduced, gradually, through a side pipe. The sulphur 

 melts, then vaporizes, and combines as vapour with the incandescent 

 carbon. The gas escapes through a top pipe which communicates with 

 two reservoirs, the first of which retains entrained sulphur, the second, 

 which is cooled by a bath of cold water, condenses the vapours of carbon 

 disulphide. The uncoudensed gases, which are hydrocarbides, escape 

 through a top pipe. Carbon disulphide flows into zinc reservoirs, where 

 it is preserved under water. It may be rectified by drying it over 

 fused calcium chloride and finally distilling it on a water-bath. For 

 agricultural purposes, this rectification is' useless ; carbon disulphide 

 in that case is led directly from the tank into the wrought- iron barrels, 

 in which it is dispatched. The annual production of this product in 

 France exceeds 2000 tons, almost the whole of which is used in 

 agriculture. 



Properties. — Carbon disulphide is a colourless liquid with a 

 pleasant smell when it is pure, but almost always fetid on account of 

 impurities which it contains. It is a very mobile liquid, which boils 

 at 45° C. (123° F.), and consequently vaporizes with rapidity in an 

 open vessel. Its vapours form with air mixtures capable, like coal 

 gas, of detonating at the approach of a flame or an incandescent ob- 

 ject. Owing to its ready inflammability the manipulation of carbon 

 disulphide necessitates great precautions, and should be carried out 

 far from any source of heat or flame, and wholly in the open air. 

 Smoking is therefore forbidden in the sheds where it is handled, and 

 when it is employed in the field the iron barrels containing this pro- 

 duct should be deposited far from dwellings, and protected from the 

 sun. To prevent the losses which would result from the evaporation 

 from a cask being emptied, a good precaution is to run a small quantity 

 of water into the cask. The water forms on the surface of the carbon 

 disulphide a protecting layer, for the density of the water is lower 

 than that of the sulphide. To ascertain the quantity of this liquid 

 left in a barrel, a rod coated with tallow may be dipped into it. The 

 rod will come back clean on all the part which touched the carbon 

 disulphide, this product being a solvent for all fats. Carbon disulphide 



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