110 



deeper than is necessary so that the wound may soon be healed by the 

 formation of new bark. 



Yield. — Messrs. Silver of Silvertown India Rubber Company re- 

 ported on samples sent to them in 1888 that one quart of juice yielded 

 one pound of dry and washed caoutchouc, or about 22 ounces of ordi- 

 nary crude caoutchouc, but the sample sent in 1890 yielded only at 

 the rate of two ounces per quart. Probably the difference was due to 

 collection in the former case during the dry months and in the latter 

 during the wet season. The value of the rubber in 1890, was stated 

 by Messrs. Silver to be 3s. 2d. per pound. 



Preparation of the Rubber. — The rubber coagulates simply on expo- 

 sure to a dry atmosphere, but from experiments made, it is probable 

 that the method described under Assam Rubber as the one used on a 

 large scale would prove the most successful. 



Propagation. — This plant may be propagated by seed, or readily by 

 cuttings. 



Colombian Scrap or Colombia Yirgex Rubber. 



Mr. Robert Thomson, of Bogota, Colombia, in 1388 described this 

 rubber as follows, as reported in the Kew Bulletin : — 



" This rubber is known in commerce as Colombia Virgen. It has 

 been exported chiefly to the United States, and next to the Para rub- 

 ber, it has realized the best prices in the market 



" I have established in this country during the last five years a plan- 

 tation of this rubber, consisting of about 70,000 trees, this being, I be- 

 lieve, as yet the only plantation made of this sort. Under cultivation 

 this tree thrives admirably, growing with great rapidity, and averaging 

 about five feet a year. 



Crops are obtainable in from six to eight years, but a tree five years 

 old yields as much as 1 lb. of rubber. It is a large forest tree, the 

 trunks attaining six and seven feet in circumference. Four arrotas 

 (100 lbs.) of rubber have been extracted from a single tree, but the 

 average yield is far less 



" The important consideration as regards this species, apart from its 

 intrinsic value, is that it grows at great elevations on the Colombian 

 Andes, viz., at from 6,000 to 8,000 feet above the sea. 



" Prior to the wholesale destruction of this tree (but few now re- 

 main) by the rubber collectors, I explored some five years ago, the 

 forests wherein it abounded in order to examine the soil, climatic 

 and other conditions affecting its growth. It may be mentioned that 

 its area of distribution has been peculiarly limited to a small section of 

 the Cordilleras some 1,500 miles from the sea. The total quantity of 

 rubber exported during the few years the article existed could not have 

 amounted to many hundred tons. 



" It is very difficult to propagate the tree from cuttings, hence I have 

 had to resort, during my supervision of the plantation, to propagation 

 from seed, which, moreover, were always procured with much difficulty." 



Messrs. Hecht, Levis, and Kahn, write in May, 1890, to Royal Gar- 

 dens, Kew : — 



" We beg to say that Colombian scrap rubber has been known in 

 the market for the last few years, and is of a very superior quality 

 indeed. 



