RUBBER AND RUBBER MANUFACTURE 5098 RUBBER AND RUBBER MANUFACTURE 



Practically all the commissary supple 

 ammunition required by the American troops 

 south of the Rio Grande in 1916 were trims- 

 ported in motor trucks. An nutomobili 

 of 18,000 i mployed by the French 



BRANCH OF RUBBER TREE 

 The illustration is that of the hevea, the 

 source of Para rubber, the best in the world. 

 :i only a few months old the tree is as 

 tall as a man, and eventually reaches a height 

 of over a hundred feet. 



to rush reinforcements and munitions to Ver- 

 dun during the first hours of the great German 

 drive against that fortress in 1916. Napoleon 

 : that an army marches on its stomach; a 

 modern army marches on rubber. Rubber is 

 as vitally a contraband of war as iron, steel and 

 gunpowder. 



Rubber Manufacture. The balls of crude 

 rubber, when received at the factory, contain 

 dirt and other impurities. The cakes are cut 

 into small chunks which are run through a set 

 of rollers over which water is flowing. The 

 rubber comes from the washing machine in 

 irregular strips with rough surfaces. These 

 strips are dried and then taken to the mixing 

 machine, where sulphur and occasionally other 

 substances are mixed with the rubber to adapt 

 it to the uses for which it is desired. The pre- 

 pared rubber, then in the form of sheets, is 

 ready for manufacture into the goods for which 

 it is designed. For tires, belts and shoes it is 

 combined with duck or some other strong fabric 



by laying the sheet of rubber on the cloth and 

 passing them between rollers which press them 

 together. Tubing is made by passing soft rub- 

 ber through a mold. Cloth for mackintoshes 

 or raincoats is prepared by laying a thin sheet 

 of rubber between two layers of cloth and 

 pressing them together between rollers. 



The Story of Rubber. The Spaniards who 

 followed Columbus to the western world some- 

 times saw the natives playing with balls made 

 of the hardened milky juice of certain tropical 

 trees. Later they learned that by putting a 

 coating of this juice over their coats or shoes 

 they could make them waterproof, and that the 

 natives of some of the countries molded water 

 vessels of this material, and even boots, which 

 when smoked looked very much like leather. 

 The name India rubber, the India part of which 

 is little used now, originated in the eighteenth 

 century in England, where it was noticed that 

 the substance would erase or rub out pencil 

 marks. Another name is caoutchouc, a word 

 supposed to be Brazilian for weeping wood. 

 The French still say caoutchouc. The Ger- 

 mans prefer gommi and the Italians and Span- 

 iards goma, words which remind us that foot 

 rubbers were once known in America as gums 

 or gum shoes. 



Not quite a century ago rubber began to as- 

 sume importance in the northern world. It was 

 in 1820 that a sea captain brought to Boston 

 the first of the famous gum shoes, made in 

 South America by dipping shaped pieces of 

 wool into the rubber juice; clumsy as they 

 were, it is said that over a million of them were 

 sold before a better process was discovered. 

 In 1823 the Scotchman who has left us his 

 name in the raincoats called mackintoshes took 

 out his patent, which was for placing a very 

 thin sheet of rubber between two layers of 

 cloth. Meanwhile an Englishman, Hancock, 

 had discovered that pure rubber can be made 

 into blocks or sheets of any shape by mechan- 

 ical pressure. But in spite of all these ingeni- 

 ous contrivances rubber would have remained 

 of minor importance had it not been for a 

 fortunate discovery made in America in 1839. 



Vulcanization. The rubber goods made in 

 these early times would make us laugh to-day. 

 They were ordinarily rather sticky, and in hot 

 weather very much so, while in cold spells they 

 became stiff and somewhat brittle. Charles 

 Goodyear, whose story is told in another vol- 

 ume, made an end of this disconcerting weak- 

 ness when he found that rubber mixed with 

 sulphur and then heated to the melting point 



