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native-prepared product of the Para rubber tree the best of all grades 
of rubber, but as the method is not only very expensive and exceed- 
ingly tedious, but also harmful to the health of the operators, the 
inventor of the Da Costa coagulating plant thought of devising a 
means of doing mechanically all that is now done by hand in the 
rubber forests of Brazil. This plant, which is the result of practical 
experiments and tests by Mr. Da Costa, and is made by Messrs. David 
Bridge & Co., the well-known Bubber Engineers of Castletoh, Man- 
chester, needs no chemicals whatsoever, so long as tropical forest woods 
are available for heating the boiler, as well as green foliage of palms 
for generating smoke in the boiler furnace. 
The coagulating and smoking by means of this plant is the simplest 
of all operations in the rubber industry, and may be performed by any 
inexperienced hand, the process being as follows : . .... 
The latex, being brought from the field, is strained if it is found to 
contain mechanical impurities, and then poured into the coagulating 
tanks. Steam is meanwhile being raised to about 30 to 35 lb. in the 
boiler, forest woods alone being used for fuel. On to the burning wood 
I in the furnace are then thrown green palm leaves, nuts, or any green 
twigs of tropical trees, the distillation of which produce acetic acid, 
whilst the fumes of the green foliage would be found to contain creosote 
to some extent. These fumes are accumulated in a special receptacle 
after being cleared of cinders, &c,. and are then forced into the coagu- 
lating tanks by a steam injector. _ 
The force of the steam violently agitates the latex, and during this 
operation every particle of it is reached by the smoke. In about ten 
minutes or rather more if the quantities to be dealt with are very 
large, caoutchone globules coagulate and separate from the lyes and 
rise in the surface, , - . 
The coagulate substance, after being allowed to cool oh in the 
tanks, is afterwards taken to a small press and turned out in the shape 
of flat block rubber. These, in their turn, are then re-bloeked into club 
form, and after being dried, either in a stove or vacuum, are ready foi 
* shipment. If the flat blocks are only lightly compressed into the 
form of cubes, whilst still being sufficiently air-tight in the centre to 
prevent discoloration setting in, they can be easily torn asunder by the 
manufacturers and used in their machines, without the extra labour of 
imeviously cutting them into convenient sizes. 
Bubber prepared in this way retains all the native elements, as 
regards resiliency and tensile strength, of fine hard native Bara, and 
will last as long as the wild rubber— if kept in a crude state, for years. 
It is claimed for this coagulating plant; therefore, that it not only 
has the advantages of dispensing with the assistance of chemical agents 
in a liquid form but also allows the producer to send to the market 
the only preparation that satisfies all the rubber manufacturers’ require- 
ments at the various manufacturing centres throughout the world. 
In addition to this, the inventor claims that it also possesses the 
unique property of being the only apparatus which can convert the 
latex of the Castilloci elasteca into a rubber of equal market value, 
appearance, and colour, to that of the best Bara sort exported from 
Brazil.— Tropical Life . 
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