218 CAOUTCHOUC AND GUTTA PEKCHA 



I 



wonderful elasticity and utter impermeability by water, it w 

 only within the last forty years that caoutchouc has risen into 

 importance, as before that time no cheap solvent had been 

 found out which, on evaporating, would allow it to assume a 

 variety of useful forms, with the retention of all its useful 

 qualities. 



In the year 1820, a Mr. Nadler discovered the art of cutting 

 it into thin threads that could be woven with wool, silk, or 

 cotton, into elastic tissues, but this invention was soon eclipsed 

 by that of Mr. Mackintosh, who, by dissolving caoutchouc inJ 

 petroleum and spreading it between two pieces of wool or* 

 cotton-stuff, united them by pressure into a water-tight cloth 

 which, though heavy, expensive, and of a disagreeable smell 

 was justly considered as a most useful fabric for a rainy climate 

 Since that time the manufacture of caoutchouc tissues has made 

 rapid strides to perfection, particularly since the volatile oil 

 which is produced by the dry distillation of the resin itself, was 

 found to be its best solvent. 



About twenty years ago, overshoes or galoshes of India 

 rubber first began to be manufactured, but as they had the great 

 fault of becoming soft and adhesive when exposed to warmth 

 and of hardening and contracting in cold weather, this branch 

 of industry would never have acquired a great extension, if, 

 about the year 1845, Messrs. Hancock and Eroding had not 

 found out that, by the addition of a small quantity of sulphur to 

 caoutchouc, the latter, without losing any of its elastic qualities,, 

 acquires the property of retaining the same consistency through 

 every change of atmospherical temperature. By this discovery, 

 to which the strange name of vulcanisation has been given, 

 new field was opened for the use of caoutchouc ; but the march 

 of progress did not stop here, for a few years since, in America, 

 Mr. Groodyear, by adding about twenty per cent, of sulphur to 

 caoutchouc, converted it into a hard substance, capable of being 

 used, in many instances, instead of wood, horn, or tortoise shell 



If fifty years ago one might ask what caoutchouc was good fo: 

 besides effacing pencil-marks, its uses are now so manifold thi 

 it would almost take a volume to describe them. A small 

 quantity of it dissolved in rape seed oil makes an excellent mix- 

 ture for greasing machinery, as it remains fluid at every tempi 

 rature. Melted and mixed with finely powdered slaked lim- 



