475 



of the very important uses of rubber and is responsible for the 

 consumption of a great part of the fine Para imported. Here 

 probably plantation rubber would be of great use, being pale in 

 colour, clean and free from offensive odour, provided that the 

 lasting properties of the rubber are not injured in the preparation 

 Fabrics are coated with rubber in two ways. The rubber may 

 be made into dough by masticating and mixing with sulphur and 

 other ingredients and spread in this condition on the fabric by 

 means of heated rollers ; or the rubber, sulphur and mixings arc 

 made into a paste with a rubber solvent and this paste is spread 

 on to the fabric by the aid of rollers, and the solvent dried off by 

 passing the fabric over plates heated by steam. 



For vulcanisation, the heat cure, using steam or water, is 

 usually adopted. The machinery necessary for spreading rubber 

 is heavy and costly, the rolls are of polished steel about 2 feet in 

 diameter and each machine has at least three, and may have four, 

 rollers arranged vertically above each other on horizontal axes. 

 The fabric is rolled over the top roller, round between this and the 

 second, and even tension being thus given to the cloth, and finally 

 it emerges between the second and third. The rubber as dough 

 or paste is spread on to the fabric from the face of the third roller, 

 as the cloth passes between it and the second. There are machines 

 for spreading simultaneously on both surfaces of the cloth, and 

 many different details in the actual mechanism of the spreading. 

 The "rolls are called calenders and the machines are very similar to 

 the calendering machines used in paper manufacture. 



31. There are many forms of india-rubber goods which cannot 

 justly be placed under any of the three previous clauses, but which 

 deserve some mention here, especially as they are made for the 

 great part from rubber of the finest quality and for which planta- 

 tion-grown rubber is at present never used. 



CUT-THREAD AND SHEET. 



32. Cut-thread is the name given to rubber in the form of 

 thread, or strands of square cross section cut from solid sheets 01 

 rubber already vulcanised. This rubber thread which when fine is 

 woven into elastic webbing, is all of the best possible quality, and 

 special nerve, elastic and keeping properties are demanded. 1 he 

 amount of labour which is actually spent on the rubber would 

 make it a false economy to use untried cheap rubber and make s 

 of cut-thread will not use at present plantation rubbe r for *h« 

 process. Each manufactory has its own s P e . c ! al Q ™™ 

 actually cutting the thread and details of the ^ chine "^ 

 guarded as secrets. I was, however, admitted in 



!nd saw rubber being actually cut into threads by mult pie scissors 

 and knives, the thread afterwards being powdered and spooled and 

 wound into hanks. The details of the cutting I shall not attempt 

 to describe. , . , • 



Cut-sheet is made from large blocks 

 about half a ton, the cutting being done by a blade four to six 



