188 ON THE MILK-SAP 



such extensive application in manufactures, that a closer 

 acquaintance with it will certainly not be uninteresting. 

 The English use this peculiar product of the vegetable 

 world most largely. In 1830, more than twenty-six tons 

 were imported into England. In the year 1829, nearly 

 fifty tons. In the customs'-year, ending in 1833, duty 

 was paid on more than eighty-nine tons. Since that time, 

 the consumption has been continually increasing. In one 

 manufactory in Greenwich, alone, eight cwts. are daily 

 submitted to dry distillation in iron vessels. The residue 

 is a peculiar greasy substance, which never loses its tenacity 

 and pliability, bidding defiance to every influence of air or 

 water; and it is, therefore, made use of in the English 

 navy for steeping the cordage in, to render it more durable. 

 The fluid distilled over is a volatile, inflammable oil, which 

 possesses the property of readily dissolving Caoutchouc, and 

 leaving it, after evaporation, in its original condition. 

 Thus it becomes possible readily to give the Caoutchouc 

 any desired form, and to impart its impenetrability by air 

 and fluids of almost all kinds, to every other substance. 

 Thus are produced the many waterproof fabrics, one of 

 which has been called after its discoverer, Mackintosh. The 

 great elasticity is also turned to account in the greatest 

 variety of ways, this property being in the highest degree 

 valuable for many purposes. For this, the great masses of 

 Caoutchouc are cut by proper machines, first into thin 

 plates, and then into very fine filaments. These filaments 

 are covered with linen, cotton or silk thread, and then 

 woven with other customary yarn, which serves as the 

 woof, into bands, &c. Finally, Caoutchouc in an unpre- 

 pared condition, is applied to many uses, of which I will 

 only mention the so-called " goloshes," or India-rubber 

 shoes. 



