r 7 2 
the vvashwater in the form of a snow-white cake of rubber of such 
strength and toughness that it can in one mass be lifted -out from 
the barrel. On cutting this cake open, it will be found that it is 
rather spongy, being full of little holes which are still filled with 
some of the albuminous, though very dilute, mother liquor. If, 
therefore, the rubber were dried in this state it is obvious that it 
would still contain a small quantity of the objectionable albuminous 
matter. For this reason the rubber contained should at once be 
taken, cut into strips, and subjected to a thorough washing upon 
an ordinary rubber washing machine. As all albuminous matter 
present is still in a state of perfect solubility there is no difficulty 
whatever of completely removing every trace of it by carrying out 
the washing with a plentiful supply of water on the washing rollers. 
The rubber thus obtained is a product of a degree of purity in 
which no rubber, not even the finest brands of Para, has ever been 
offered to the manufacturer, ft is absolutely free from solid im- 
purities of any description, it contains no trace of either soluble or 
insoluble organic or inorganic impurities. Of course it contains a 
small amount of resinous matter combined with only a trace of the 
constituents known as “ash.” The amount of these resinous mat- 
ters is extremely small, and they are of an entirely innocuous 
nature, so that any attempts to remove them, which would call for 
a somewhat energet’c chemical treatment, would be altogether out 
of place. In a further communication I intend to give the analy- 
tical data of this pure Castilloa rubber. 
When dry, the condition in which the owners of the Las Cascadas 
plantations intend to ship this rubber, it forms a product which re- 
quires no preparatory operation on the part of the rubber manu- 
facturer, but which may at once be taken into operation for the 
manufacture of rubber goods of every description. Nor need any 
fear be entertained that rubber of this description is in the least 
liable to suffer such detrimental changes during transit in the ships’ 
holds, which are at present so common owing to the “heating” 
(fermentation) of the rubber during transit. Indeed, a considerable 
lot of this which was purposely packed and shipped in the exces- 
sively wet condition in which it came off the rubber washer, had not 
undeVgone the least change, still less any deterioration on reaching 
this country. 
An analysis of a sample taken of one of these dry sheets for rub- 
ber gave the following results : — 
Resinous Matter - - - 2 61 p.c. 
Ash - - - 0-44 p.c. 
Nitrogenous Constituents - Nil. 
Insoluble Constituents - Nil. 
The sheets themselves are extremely light in colour, semi-trans- 
parent, and when dissolved in the usual rubber solvents form almost 
glass clear solutions. The characteristic rubber smell is almost 
entirely lacking, certainly much less noticeable than in even the 
finest Para rubber. The strength of these sheets is distinctly 
superior to that of washed and dried sheets of Para rubber. How 
this Castilloa rubber after vulcanisation compares with Para rubber, 
