412 FOREST PRODUCTS 



Various methods of vulcanizing rubber are in common use at the 

 present time. The method generally followed consists of kneading the 

 crude rubber after it is washed and dyed with varying amounts of sulphur. 

 It is later reduced to proper shape by cutting into small pieces and then 

 running it through rollers. In general, there are two kinds of rubber, 

 naturally hard and soft rubber. Hard rubber is often called " ebonite " 

 in the trade. There are many classes of finished forms of rubber, each 

 of which requires a different kind of treatment and a distinctive process 

 of manufacture. The principal classes of rubber may be divided as 

 follows : 



1. Footwear. 



2. Waterproof garments. 



3. Mechanical goods, such as tires, belts, etc. 



4. Electrical and scientific apparatus and articles. 



5. Medical and surgical appliances. 



6. Liquid or semi-liquid goods, such as varnishes, cements, etc. 



PRINCIPAL USES 



There are no statistics available to show the utilization of rubber 

 in this country. An authority on rubber and its uses estimates the value 

 of the different forms of rubber products as follows : 



USES OF RUBBER 



Uses. . Value. 



Automobile tires $250,000,000 



Mechanical goods 200,000,000 



Solid tires 1 75,000,000 



Boots and shoes 100,000,000 



Clothing, auto topping and similar goods. . 75,000,000 



Automobile tubes 70,000,000 



Rubber insulated wire and insulation 65,000,000 



Druggists' sundries 30,000,000 



Miscellaneous 30,000,000 



Hard rubber 15,000,000 



Motor cycle, bicycle tires, etc 10,000,000 



Rubber cements 5,000,000 



Total annual value $1,025,000,000 



