CHAPTER XVI. 

 KINDS OF PARA RUBBER. 



Plantation and fine hard Para — Uses of Plantation and cultivated 

 rubber — Burgess on Plantation rubber and its inferiority — The effect 

 of moisture and Bmoking on Plantation rubber — -Chemical and 

 physical tests — Commercial reports on Plantation rubber from Ceylon 

 and the Straits — Biscuit and sheet rubber — Gripe rubber, characters, 

 preparation, and value — Worm rubber, characters, preparation, 

 and value — Illustration showing forms of Plantation rubber — Lace 

 rubber, preparation by mechanical means — Illustration of machinery 

 used in the manufacture of lace rubber — Flake rubber — Scrap rubber 

 — Chemical analyses of biscuit, crepe, lace, and worm rubber. 



The Difference between Plantation and Wild Rubber. 



THE comparison of the kinds of Para rubber may appropriately 

 be prefaced by a few remarks regarding the differences 

 between Plantation and Wild or fine hard Para rubber, the former 

 being obtained from the newly-planted trees in the Tropics and the 

 latter from the wild trees in the Amazon District. 



The methods of preparation in the East are such that Plantation 

 rubber is made much purer than the fine hard Para ; it contains very 

 little, if any, moisture, and is obtained with or without the use of 

 chemical reagents. It is, of course, usually obtained from younger 

 trees than the fine hard Para. The Plantation rubber, when placed 

 on the same market as the "wild," obtains a higher price, weight for 

 weight, because of the small quantity of water and other impurities 

 present, the loss on washing being only about 1 per cent, as against 

 10 to 20 per cent, for some grades of fine hard Para rubber. The 

 extraction of the impurities from the latter rubber is not always very 

 troublesome, and if allowance is made for the large quantity of water 

 it contains the (nice realised is really much better than that for 

 Plantation rubber free from moisture. 



The preference of the manufacturers for purified fine hard Para 

 rubber is said to be due not bo much to its being obtainable in large 

 quantities, as to the fad thai its properties are much more constant 

 and lasting. 



The "India Rubber World "" uf December 1st. states that several 

 manufacturer^ in Great Britain are unable to give their opinion as 

 to the value of Plantation Para rubber, but they all seem agreed 

 that there is a wide variation in the quality as received in England. 



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