2 5 
other some 3 ^ miles distant, in the middle of the rubber plantation. 
In the future an electric tram system will be laid out to facilitate 
transportation on the estate. The .new Pan-American railroad 
passes within a few miles of the plantation buildings, and La 2a- 
cualpa station will mark the place of communication with the outer 
world. 
The Preparation of Rubber. 
At present the rubber factory is in temporary quarters under 
the roof of the estate saw-mill. A proper factory building will be 
erected next year. Briefly stated, the system of preparing rubber, 
which will then be adopted, is as follows : — The latex brought in 
from the field is emptied into a, collecting tank, where an equal 
amount of water is added. Inside this tank is an endless screw 
which slowly revolves and thus mixes the latex and the water 
without causing a separation of the natural clumps pf globules. 
In case the preparation has to be postponed, a small amount of 
dilute formalin is slowly added from an automatic drip can. From 
the collecting tank the latex passes through a strainer into a 
stirring vat, where more water is added and the mixture is well 
stirred ; the temperature being slightly raised with steam passing 
through pipe coils inside the vat. 
If we adopt a smoking or fumigating process, which is not yet 
definitely decided, the latex would next pass into a zinc cylinder 
and through a series of sieves between which the fumes are 
pressed. The thoroughly fumigated latex falls into a vessel, 
whence it is run off, fifteen minutes later, into settling tanks. Here 
the creaming of the latex takes place, and by very gentle stirring 
of the top layer of “cream” coagulation is assisted. Sometimes 
a coagulant has to be added, but more ‘often the latex shows a 
tendency to coagulate too rapidly, f^rom time to time some of the 
mother liquid, which is dark brown, resembling beer, is drawn off 
from below and clean water is slowly added. 
The coagulated rubber slabs p^re parsed on to the washing 
machine, and after a thorough washing, the subber is dried in vacuo. 
It is very difficult, even by adding coagulants, to effect 
the coagulation of all the rubber in the latex. As an adjunct to 
the creaming process all of the remaining latex, after two cream- 
ings, is passed through a centrifugal separator, and after this the 
mother liquid does not contain any more rubber. 
All the rubber is pressed into blocks in a strong screw press 
after drying. Two years ago Mr. Harrison prepared with tartaric 
acid on La Zacualpa a big rubber block as an experiment, and it 
proved to be the most attractive and practical way in which we can 
ship the clean plantation Castilla. I have received the advice from 
English rubber brokers to send Castilla rubber as crepe, but I 
greatly doubt the advisability of this, as the oxidation would be 
considerable, and Castilla suffers more from this than Para rubber. 
Sulphurizing the Latex. 
The addition of finely pulverized sulphur by a process corres- 
ponding to the vulcanization suggested itself, in the early stages 
of my experiments with Castilla latex in the laboratory at La 
