262 



shoulders also bruise the bark if the cutting is by blows. Bull. 

 No. 49, Bureau of Plant Industry. 



*Mr. Hart states that "the invention of the new tool described by 

 Dr. Weber is a step in the right direction, and working on the same 

 lines we are now in possession of an instrument which allows still 

 more freedom to the operator and enables him to make a narrow, 

 deep, or broad channel at will, with ease and despatch." 



Washing the latex — By the methods now adopted the foreign 

 matters are washed out of the latex before coagulation takes place, 

 thus producing a very high grade of rubber from the Castilloa, 

 having a marketable value equal to that of Para. 



Until now it was generally assumed that the Central American 

 rubber was of much inferior grade to that of Para. It has now 

 been proved, however, that the actual difference is very slight, if 

 there is any, and resolves itself into the question of preparing it 

 for the market at the time of tapping. During the past few months 

 the best qualities of some rubber from cultivated Castilloa trees 

 brought $1.54 and $1.56 gold per pound in the London market. 

 This price was higher than that of best South American Para sold 

 at the same time. 



Coagulating the latex — " The separation of rubber from the latex, 

 a process commonly called coagulation, is in a somewhat more 

 advanced state of investigation than the subject of tapping, if, 

 indeed, the recent experiments of Dr. Weber do not mean that a 

 final and satisfactory conclusion has been reached. Dr. Weber 

 finds that by the simple expedient of diluting the fresh latex of 

 Castilloa with five times its volume of boiling water and adding 

 8 ounces of formaldehyde to each barrel of the resulting fluid, all 

 the impurities to which the inferiority of Castilloa rubber are due 

 can be removed, since they will remain in solution, while after 

 twenty-four hours the clean rubber will be found in a " snow-white- 

 cake" which can be lifted off the top. Dr. Weber contends that 

 rubber prepared in this way is " absolutely free from solid im- 

 purities of any description either soluble or insoluble, 



organic or inorganic," and that it is equal or superior to the finest 

 brands of Para rubber. Bull. No. 49, Bureau of Plant Industry. 



Yield — "It may be said that at the present stage of this inquiry, 

 2 pounds per tree is looked upon as the reasonable maximum yield 

 to be expected from adult trees of twelve years and upward, grow- 

 ing under favourable natural conditions. This is the highest 

 estimate which is known to the writer as having been made by 

 reliable planters of intelligence and experience ; and some such 

 hold that the probabilities lie nearer to half a pound than to 2 

 pounds. It is appreciated that this estimate is much smaller than 

 many claims based on wild trees and that it is much larger than the 

 results reached on some of the earlier plantations would seem to 

 promise, The estimate is not, however, made as an average of all 

 published figures, but is reached rather by the elimination of un- 

 warranted expectations from one end of the series, and from the 



* Bull. R. Botanic Gari£n£, Trinidad, 1905, p. 163. 



