The suburban citizen., 1900-03-03
SUBSTITUTE FOR RUBBER
THE CUM SUPPLY GETTING SHORT,
81 ITS USES INCREASING.

the supplies of these gums do not in
crease in like proportion and even
threaten to become smaller in few
years unless extraordinary means are
taken to keep them up, have led to
many attempts on the part of inven-
tors to produce some substitute which
would fill their place at least for some
important commercial uses. The re-
cent rapid extension of electric install
lation with the attendant call for insu-
lation of miles aud miles of conductors
has emphasized the demand for rub
Der and guttG percha substitutes for
insulating purposes, and the PROPOSE
ton now being actively agitated to
extend the great sea cable telegraph
service OF the world by laying sub
marine cable from the United States
to the Philippines makes the question
of immediate interest,
The consumption of rubber is esti-
mated at 10000 tons a year. The
finest quality as well as the largest
quantity sent from any one region,
comes from the Para district in Brazil
and the recent nigh prices and great
demand for the extra-elastic sorts for
bicycle, wagon and automobile tires
have so stimulated the work of the
Brazilian rubber gatherers that in
1898 the exports from Para reached
about $4,000 tons, as against $4,000
the year before Reports from that
district indicate q serious danger Of
exhausting the rubber trees unless u
systematic method is adopted of re-
planting, and considerable interest
has been evinced in other parts of the
world regarding the possibility Of
growing rubber trees successfully.
Experiments in this gdirectiop have
recently attracted attention in Mex
leo. No substitute which has yet
appeared seems to offer Success for
those purposes which put the strength,
durability and elasticity Of Para rub
Der to their most severe tests, but
considerable progress has been made
in providing substitutes of like quail
ties for q number of other uses, and
notably for that Of electrical insula-
ting. The Singapore rubber is the
variety best fitted for work of this
sort and the shipments of this do not
increase, and in 1898 amounted to
only about $500 tons. The last At
lantic cable took 500 tons of Singapore
rubber to insulate it and a Pacific ca
BILE would take a much larger amount.
In land purposes, such as the many
miles of cables which are being laid
for telephone, telegraph and power
purposes and which are inclosed in
lead, paper has become the favorite
insuator. For telephone purposes it
is superior to all others because of its
low self-induction, which makes talk
ing over a line of paper insulated wire
as easy as whispering into an adjacent
ear, while rubber aud gutla percha
both have a deadening effect upon the
sounds. Power cables, such as those
which the Third avenue road is now
laying for its under trolley lines, are
insulated with paper, but in this case
it is laid over the bundle of wires that
form the conductor in compact form,
while for the telephone and telegraph
wires the paper is twisted lightly
about them with air spaces left among
the wires running the whole length of
the cables. With paper insulation it
is imperative that water shall be ex-
'cluded and all the cables in which it
is used are leadencased and this
waterproof covering is carried along
unbroken to the cable heads and here,
in turn, the covering is connected by
soldering to watertight connections
with the Office wires. For submarine
purposes paper could not be used
The inventor who wished to find n
substitute for rubber and gutta percha
naturally turned toward other vegeta-
BILE products for a baHe and consider
able success seems to have been at
tanned by a number of clever men in
this direction. Some time ago, there
was described in the Sun a process by
which linseed oil was turned into
fair substitute for rubber, made capa-
BILE of yulcanization and of taking the
place of rubber for many uses. The
linaeed oil in this process was pre-
pared by oxidation, changing it's
character just as it changes when it is
applied to surfaces as paint. The
principal point in this invention was
the method Of oxidizing the oil thor
oughly. This was accomplished by
dipping punches of tow into the oil
and then exposing the oil thus subdi-
vided on the flaments of tow to the
action of warm air. A large factory
was built in England to manufacture
articles under the patents which cover
this process.
A later process, which has been de
scribed recently, uses linseed oil as a
basis also, but treats it instead with
nitric acid. The product is called
velvril. 1t is composed of a mixture
of nitrated oil and nitro-eellulose.
Either inseed or castor oil may be
used. The nitrated oil is prepared
first and the nitro-cellulose is added
to this. A homogeneous mass is OBJ
tanned whose final qualities of hard
ness and elasticity may be altered by
varying the proportions of the mix
ture. The proportions which yield a