C96 



CAOUTCHOUC 



gas-apparatus ; the nuisance of these products led to many inconveniences. Mr. Mac- 

 intosh, then employed in the manufacture of cudbear, in 1819 entered into arrange- 

 ments with the Glasgow Gas Works to receive the tar and ammoniacal products. 

 After the separation of water, ammonia and pitch, the essential oil termed naphtha 

 was produced, and it occurred to him that it might be made use of as a solvent for 

 India-rubber, and by the quality and quantities of the volatile naphtha, he could 

 soften and dissolve tiie India-rubber. After repeated experiments to obtain the mix- 

 tures of due consistency, Mr. Macintosh, in 1823, obtained a patent for waterproof 

 processes, and established a manufactory of articles at Glasgow, and eventually, with 

 partners, entered upon the extended scale of business at Manchester, now so well 

 known as the firm of Charles Macintosh and Co. 



The action of many solvents of India-rubber is first to soften and then to form 

 a sort of gelatinous compound with India-rubber, requiring mechanical action to 

 break the bulk so as to get complete solution, when the original bulk is increased 

 twenty or thirty times to form a mass : it may be imagined that in the early trials 

 much time was occupied, and manual labour, to break up the soft coherent mass, &c., 

 while hand-labour, sieves, the painters' slab and muller, and other simple means were 

 resorted to. 



Macintosh, Hancock, and Goodyear, alike record the simple manipulations they first 

 employed, and the impression produced at the last, when they compared their small 

 personal efforts with the gigantic machinery now used to effect the same results. 



Mr. T. Hancock's first patent was in April 1820: 'For an improvement in the 

 application of a certain material to various articles of dress and other articles, that 

 the same may be rendered elastic.' Thus, to wrists of gloves, to pockets to prevent 

 their being picked, to waistcoats, riding-belts, boots and shoes without tying and 

 lacing, the public had their attention directed. To get the proper turpentine to 

 facilitate solution, and remedy defects of these small articles, and to meet the difficul- 

 ties of practice and failures, Mr. Hancock gave constant zeal, and pursued the subject 

 until, united with the firm of C. Macintosh and Co., ho produced one of the most impor- 

 tant manufactures known. 



To get two clean pieces to unite together at their recently-cut surfaces, to obtain 

 facile adhesion by the use of hot water, to cut the India-rubber by the use of a wet 

 blade, to collect the refuse pieces, to make them up into blocks, and then cut the 

 blocks into slices, were stages of the trade which required patience, years of time, and 

 machinery to effect with satisfaction to the manufacturer. 



To operate upon the impure rubber was a matter of absolute necessity for economic 

 reasons : the bottles made by the natives were the purest form, but larger quantities 

 of rubber could be cheaply obtained, full of dirt, stones, wood, leaves, and earth. To 

 facilitate the labour of cutting or dividing, Mr. Hancock resorted to a tearing action, 



403 



and constructed a simple machine for the purpose. (Seo.^. 403). A shows the en- 

 trance for pieces of rubber ; B, interior of fixed cylinder, with teeth ; c, cylinder to 

 revolve with teeth or knives ; D, the resulting ball of rubber. 



This machine had the effect of tearing the India-rubber into shreds and small 

 fragments by the revolution of a toothed roller ; the caoutchouc yielded, became hot, 

 and ultimately a pasty mass or ball resulted ; when cooled and cut it appeared homo- 

 geneous. Waste cuttings put, in the first instance, on the roller, were dragged in, and 

 there was evidence of action of some kind taking place ; the machine was stopped, the 



