March 1, 1902.] THE TROPICAL AGRICULTURIST. 
611 
INDIA-RUBBER AND GUTTA-PERCHA 
AND ELECTRICAL TRADES' JOURNAL. 
Rubber Plant. — A good few people just now are 
troubling tbeir heads about the plant. We do not 
refer to that which has leaves and makes a nice orna- 
ment, but to the mass of wood and iron, in all sorts 
of shapes and sizes, that ooiistitntea a rubber factory. 
Some of it is fixed and immovable, except in the way 
for which it was made ; some of it, and a much larger 
portion than outsiders would dream of, is loose, end 
changes its location frequently. It is clear that the 
latter runs more risk of getting injured or lost than 
the former ; but, on the other hand, breakages in the 
fixed plant are usually of much greater impor auce 
when they do occur. Now that stock-taking is at hand 
with most concerns, the question crops up : How shall 
we deal with the plant this year ; shall we allow any- 
thing for depreciation— and, if so, how much, and 
what variation shall we make in the different items 1 
We have laid down here two broad divisions which 
it is well, we think, always to keep clear of each other 
— fixed plant and loose plant. Some places do not 
make the distinction. Suppose it is their hose 
plant that is in question. They have, say, a hose 
machine and a hose pan and carriage, but these are 
no use without mandrills, so they argue that the 
mandrills phould go with the other two, and all be 
considered as hose plant. The effect is, however, 
that two things get mixed up that should not be — 
the looae articles which deteriorate quickly, and the 
fixed maihines which lose their value very slowly. 
So far, the rubber industry has been rather favoured 
with regard to depreciation in fixed machinery. In 
some trades, notably the cotton trade, so great have 
been the improvements in machinery that places that 
have only seen ten or fifteen years have had to be 
all cleared out — the plant could not be run at a profit. 
The change has been complete ; the new is not simply 
the new but, in its way, it is the original, the first of 
its kind. The rubber trade has varied little. A prac- 
tical man could walk through some rubber works that 
have been going without a stop for forty years or so 
and, if he was not told, he might take it for one star- 
ted only a year or so ago. There have been some 
improvements, but they have beeu slight and, 
indeed, many of them were classed as " fads," 
with great truth, by a recent writer in this paper. 
What may be in store for ns we know not. In 
regard to one important branch, the manufacture of 
rubber shoes, we are promised by the American 
India Rubber World a complete revolution in a very 
few years. The present method i.s to be entirely 
swept away. The statement is backed by the Editor 
of that paper, a usually clear-headed and well-in- 
formed man, but we are still sceptical about it. We 
do not propose to alter our line in consequence ; and 
that is, that as regards fixed rubber machinery, a 
heavy depreoia,tion is not called for. The value goes 
down only slowly and little. There has been a 
fair quantity of second-hand machinery sold during 
this year and some of it had worked a long time, 
yet we doubt if the bulk did not realise two-thirds 
of its first cost. 
One item that is rather outside proper rubber 
machinery wants looking at carefully, however, and 
that is the engines and boilers. If these stand in the 
books at anything near their first cost they are over- 
valued. From what we have seen ourselves, good 
articles of these kinds can now be got much below 
what they were worth three or four years ago. 
There remains the very considerable portion that is 
known as loose plant to deal with, but our space is 
exhausted. We can only say that this should be trea- 
ted very liberally for depreciation if the proprietor 
desires to feel sure that his balance-sheet is on a 
sound basis. 
Bjjcovered Rubbers. — The science of recovered 
rubber does not simply end when it has been freed 
from sulphur and extraneous matter. The purest 
recovered rubber may often be the worst from the 
mauafaotariug point of view, owing to the treatment 
32 
which it has received in order to bring it to its high 
state of purity. In these days of competition there is 
everything to be said for the use of recovered rubber 
in the manufactare of a large percentage of the prin- 
cipal articles made. There are several conditions, 
however, which it is essential should be observed in 
the recovering of rul bers, and these, while not diffi- 
cult to define, are very difficult to execute in practice. 
First, it is essential that the reeovered rubhers should 
not be ar aJterated, or losded in any w*y, for the manu- 
facturer nip.y be using other flllirigs imoompatibie with 
these in the recovered rubber. He should at least be 
coufi-ient that in using recovered rubber, he is making 
use of a material which will not interfere in any way 
with the other ingredients of his mixing. 
Secondly, the manufacturer should be acquainted 
with the percentage of mineral matter present in 
the reovered rubber which he is using, and, through 
having information of its specific gravity, should be 
able to work out beforehand the density of the goods 
which he wishes to produce. 
The Rubber Chemical Co., of Mitcham, Surrey, 
are of our miud in this matter, and they believe 
that in working on these lines, they can look with 
every confidence to satisfactory increase of trade 
with their customers. 
As the real test of a reeovered rubber is after all, 
its satisfactory vulcanisation, they are prepared to 
supply samples (vulcanised) of their recovered'rubbers, 
and, further to guarantee a uniform quality and a 
uniform percentage of mineral matter and specific 
gravity on all orders. This can only be accomplished 
by carefully handling and grading of all the various 
rubbers received, and certainly no manufacture can 
show greater confidence in his efforts in this 
direction than to guarantee uniformity in every 
respect. We cordially draw attention to these facts 
here, because in gaarantying uniformity in recovered 
rubber a step is taken in the right direction of 
utilising a material in she rubber manufacture whose 
only fault is a very slight tendency to deteriorate 
quicker than Para. In any case, such a guarantee 
of uniformity is sufficient inducement for manu- 
factures to write for circulars, price lists, and samples 
to the Rubber Chemical Co., Ltd., Mitoh ,in, Surrey. 
— India- Rubber and Gutta-Percha Trader' Journal, 
Jan. 6. 
* 
MALARIAL FEVER AND THE MOSQUITO. 
(To the Editor of the Pioneer. J 
Sib, — The theory that that exasperating insect 
the mosquito is responsible for the propagation— if not 
the generation — of malarial fever, is gaining ground 
so rapidly and widely that one feels backward to 
impugn it, and still, reading the following unequivocal 
passage in that delightful book of Du Chaillou's, 
The Land of the Long Night, one cannot help feeling 
sceptical. He says at page 81 : ' Give me the plateaus 
of the Arctic regions for health. There are plenty of 
mosquitoes in summer, but no malaria at any time.' 
So far as I remember, the fundamental experiment 
upon which the supporters of the mosquito theory 
base their belief is that of the two gentlemen who lived 
under a net in a notoriously malarious district in Italy 
during the worst time of the year for malaria and 
escaped being attacked. It is argued the mosqui- 
toes did not get at the experimenters, and they did not 
sufferfrom the malaria; er^o, the mosquito bite is respon- 
sible for the fever. This reasoning is plausible but 
certainly not conclusive for may not the netting, 
besides keeping out the mosquitoes have also arrested 
the germ or atom of malaria from passing through 
to a degree dependent upon the hygrometric or soma 
other physical condition of the atmosphere ? In 
sopport of this view, I would quote the following 
passage from Dr. Moore's Family Medicine for 
India page 628; ' Sir Emerson Tenent writing of 
the fever district of Ceylou states that curtaina 
round the bed act as preservatives from disease.' 
Mr. Du Chaillou's observation quoted above is 
important, coming as it does from one who haa 
