88 RUBBER 



the best wearing article that can be made for the 

 money. 



According to the use to which rubber is to be put, it 

 has to be mixed with certain other materials, to make 

 a material that is neither too heavy nor too light, 

 too hard nor too soft, too tough nor too elastic, to 

 fulfil its purpose. And according to the price at which 

 the goods are to be sold, certain other materials must 

 be mixed with the rubber. It is with regard to the 

 proportions in which such mixings are made that the 

 manufacturers have secrets of their own which they 

 specially want to guard. The compounding materials 

 consist of such things as zinc oxide, white lead, and 

 magnesia. Always to the "dough," "mixing," or 

 " batch," as the compound is called, some sulphur is 

 added to bring about vulcanization. A colouring 

 ingredient is also put into some of the dough, according 

 to the taste and fancy of customers for whom goods are 

 going to be made. The dough is worked smooth, and 

 is then put into moulds shaped like the required 

 articles, or built up into shape and form. The goods 

 are generally vulcanized by steam heat. Much skill, 

 together with great care and patience, goes to the 

 making of all rubber goods ; and when such goods 

 have to be canvas backed, or to be made of a material 

 that is bodily a mixture of thread and rubber, the 

 process of manufacture calls for particularly good 

 workmanship. 



Printed in Great Britain by Messrs. Billing and Sons, Ltd., Guildford 



