324 
To obtain the output of commercial washed rubber, the crude 
rubber is first weighed and then washed in a flow of pure water as it 
passes between a series of rollers moving at different rates of speed. 
The result is “washed rubber ” and the difference in weight between 
it and the crude rubber represents the loss in washing. 
M. Vernet proceeds then to give the loss by washing of the 
various forms of cultivated and wild rubbers. 
Cultivated Para, No. I Crepe, biscuit, sheet or block, as made in 
the factory. This varies, pale crepe giving a loss by washing of A to* 
I y 2 per cent, while biscuits give a loss of 3 to 4 per cent. 
No 2, Clot or as he calls it Lump— the rubber which has 
coagulated in the cups-which is always he says, more or less stained 
with organic debris (it should not be) gives a loss of 5 30 P ei cen 
but when made up as crepe, only 2 to 3 per cent. 
No. 3 Scrap gives 6 to 15 per cent., Scrap-crepe 4 per cent., 
No 4 Bark-scrap in the form of crepe, 4 to 8 per cent. Wild 
Para loss on washing given by Dr. W. Esch in Fabrication de Caout- 
chouc. 
Maximum. 
Average. 
Minimum. 
Para Bolivia and Peru 
16 
14 
12 
„ Amazon Hard Cure 
17 
15 
13 
„ Island Soft Cure 
20 
18 
15 
Nanaos No. 1 
28 
26 
23 
Entrefin 
25 
22 
18 
Sernamby: Niggerhead 
40 
30 
26 
(Here we see that with the exception of Clot, giving a loss of 
30 per cent., even the scrap is cleaner than the best wild Para. Clot 
giving anything like this loss must be very unusual and is a disgrace 
to any estate.) 
I have shown elsewhere sufficiently clearly, he says, that in 
Hevea Braziliensis caoutchouc and the substances which combine to 
form it play a direct alimentary part, so that every system of too 
strong or unsufficient milking only induces a loss of Caoutchouc, it 
the tapping has a direct action on the amount obtained, can it not 
equally affect the quality of the rubber? We do not know in what 
form the rubber occurs in the laticiferous vessel, but we know it is not 
in the same state as it is in the latex when it exudes from the cut. 
If we heat Hevea latex in some vessel, we obtain a clot. If we 
heat a living branch of a tree, we, can see that when afterwards we 
break the bast bark the laticiferous tubes do not contain threads 
of rubber, though this occurs under the same circumstances in the 
stalks of rubber producing Apocynaceae. The different substances 
which combine in the formation of Caoutchouc in the latex of Hevea 
cannot be produced with equal rapidity, it follows then that the 
methods of tapping of different intensities may exercise direct and 
variable influences on the value of the Caoutchouc. 
