Gu))is. Resins, 



126 



ment of rubber plantations has caused the government to issue fraud orders 

 prohibiting fraudulent concerns from using the U. S. mail, and in order to be 

 prepared the government wished to have expert opinion upon each plantation so 

 that no injustice should be done. 



RUBBER PLANTING AS AN INVESTMENT, 



In conclusion we wish to state that after a thorough, impartial investigation 

 of the various sides of rubber planting, we feel confident that this industry offers 

 a safe and profitable investment, provided the conditions indicated above are 

 present, that is, " if soil and climate are good, and the management honest and 

 competent." With the establishment of rubber experiment stations in the hands 

 of American scientists and co-operating with the Governments of the United States 

 and the Republic of Mexico an additional safeguard for the investors will be 

 provided. — The Mexican Investor, March 1906. 



(Dr. Olsson-Seff er is the head of the new Rub ber Experiment Station in 

 Mexico, and has had much experience in rubber culture. This report, therefore, 

 may be taken as authoritative. — Ed). 



The Cultivation of the Castilloa Rubber Tree. 



THE METHODS EMPLOYED ON A NICARAGUA PLANTATION. III. 



TREATMENT OF RUBBER AFTER COAGULATION. 



After coagulation rubber is not thoroughly dry. It loses a large amount 

 of its weight the first day or so. The amount lost varies with the method by 

 which it has been coagulated, but is less in dry coagulation. It also varies 

 with the thickness of the rubber. Thin rubber loses the greater part of its 

 weight immediately, while thick rubber loses a little at a time over a long 

 period. As it dries it loses stickiness and becomes translucent. I do not believe 

 it is thoroughly dry until it is entirely translucent— of course rubber with dirt 

 and bark in it can never be entirely so— and has lost the greater part of its 

 stickiness. I have seen no rubber which had no stickiness, but it can be so far 

 reduced as to allow it to be folded on itself without cohering. Some chemicals 

 such as ammonia, will so affect latex that the rubber becomes black and does 

 not become translucent. I believe that rubber, to be at its best, should be kept 

 at the plantation in a room with artificial heat until showing signs of being 

 thoroughly dry. 



Most chemicals have peculiar effects on black water, and some on latex. I 

 do not understand these actions, but as they might lead to some discovery later, I 

 think they should be recorded. 



Sulphuric Acid :— This acid acts differently according to the strength of 

 the solution. Weak solutions of acid effect the peculiar half -coagulation of latex, 

 and turn black water pale yellowish, forming a precipitate slowly. This precipitate 

 is very fine and goes through filter paper. It settles at the bottom of the tube after 

 a few days, when it can be separated by decantation. The precipitate is pale 

 yellow, like the black water. Very strong or concentrated sulphuric acid acts 

 differently when in greater quantity than the black water. A mixture of 80 per 

 cent black water and 20 per cent concentrated acid is pale yellow, while a mixture 

 of 80 per cent concentrated acid and 20 per cent black water turns deep black. 

 Such a proportion of acid and latex does not coagulate the latex. A mixture of 

 50 per cent of each is of a deep reddish colour, and it is only when mixed in such 

 proportion that sulphuric acid causes coagulation. 



