58 THE ELEMENTS OF PLANT FOOD 



first pipe. Here it is allowed to solidify, then broken up into lumps 

 for shipment. 



Carbon disulphide (CSfe) is produced by passing 

 sulphur vapor over glowing coke or charcoal. It is 

 a clear liquid, with a pleasant odor when pure, but 

 when kept for a time, especially if water is present in 

 the vessel, it forms products which have an extremely 

 disagreeable odor. Its vapor is very inflammable, hence 

 it should be handled with care. It will dissolve rubber 

 and many other vegetable gums. It is used in mend- 

 ing rubber and making rubber cement. Its vapor being 

 poisonous is used in destroying insects and vermin in 

 rooms that can be closed tightly and left unoccupied. 



Sulphur dioxide (SO 2 ) is a colorless gas having a 

 suffocating odor. It is used for bleaching and is a 

 powerful antiseptic. It was formerly much used for 

 disinfecting rooms where contagious diseases had been 

 present. It is easily produced by burning S in the room. 

 If the room be kept filled with the gas for some time, 

 the disease germs are killed. 



Sulphuric acid (H 2 SO 4 ), oil of vitriol, is one of the 

 most important acids used by the chemist. It is a 

 heavy, oily liquid without color when pure. The com- 

 mercial acid is colored with impurities given it in the 

 process of manufacture. 



H 2 SO 4 has a strong affinity for water. It will ab- 

 sorb moisture from the air and increase its own bulk. 

 For that reason it should be kept in closely stoppered 

 bottles. It chars wood that is placed in it and will 

 convert a lump of sugar into charcoal. This action 

 is caused by its taking H 2 O from the wood or the 

 sugar and leaving simply C. The commercial prod- 

 uct is made in large quantities in the process of ob- 



