AMERICAN AGRICULTURIST, 
[February, 
r, *:> 
How India-Rubber Boots are Made. 
A pair of rubber boots is not only a great com¬ 
fort to those who, like farmers, must be out in all 
weathers, but where one must continue long at cer¬ 
tain kinds of work, almost necessary to the preser¬ 
vation of health. The manner in which crude rub¬ 
ber was affected by temperature, softening by heat, 
and becoming inflexible 
by cold, was a great 
obstacle to its employ¬ 
ment for many pur¬ 
poses, for which it is 
now used, and it is only 
since the remarkable 
discoveries of Good¬ 
year, which completely 
overcame this difficulty, 
that the manufacture 
of rubber articles in¬ 
creased to any thing like 
the present extent. 
What Goodyear’s dis¬ 
coveries were, which 
resulted in the process 
called “vulcanizing,” 
will appear in our ac¬ 
count of the method in 
which rubber boots are 
made, which is founded 
upon a visit to the 
works of “ The L. Can- 
dee & Co.,” at New 
Haven, Conn. This is 
the oldest rubber-shoe factory in the United 
States, it having been established the same year the 
American Agriculturist was founded—1842. Vul¬ 
canized shoes, by Goodyear’s process, w'ere first 
made at this establishment, and its works have 
grown to be the largest iu the country, while the 
quality of their goods is up to the highest standard. 
India-rubber is the dried milky sap of several 
different tropical trees ; these are tapped, the juice 
collected, and dried in smoke. The crude rubber 
is received at the factory in masses of various 
sizes and forms, much of it being in lumps about 
the size and shape of a soldier’s canteen. 
The first step in the manufacture is to cleanse the 
gum. It is first cut into slices by means of a large 
and very sharp circular knife, revolving with great 
speed, and kept constantly wet. These slices are 
then cut into smaller pieces by means of a “ chop¬ 
per,” a machine re¬ 
sembling in action a 
common hay - cutter ; 
afterward the pieces are 
reduced to minute par¬ 
ticles in another ma¬ 
chine, through which a 
stream of water flows, 
and washes out every 
particle of foreign mat¬ 
ter. The small particles 
of rubber, thus cleans¬ 
ed, are now shoveled 
into another machine, 
which rolls the gum 
into rough sheets. 
These sheets are then 
taken to the drying- 
room, where they are 
hung up to remain three 
months, or until every 
particle of moisture is 
expelled. These operar 
tions reduce the original 
weight as crude rubber 
from 15 to 30 per cent. 
After these sheets of gum are dry, they are con¬ 
veyed to the grinding-room, an apartment illus¬ 
trated in figure 1. On the right of the engraving 
is seen a double row of machines, called “Grind¬ 
ers,” in which the rubber is passed through heavy 
metalic rolls, heated by steam. This process soft¬ 
ens the gum, and prepares it for the admixture of 
the sulphur, which is added in proper proportions 
in another and similar machine, and thoroughly in¬ 
corporated with the gum ; the object of the sulphur, 
as already hinted, is. to render the rubber insensible 
to the changes of temperature. To accomplish this 
result, Charles Goodyear, of New Haven, devoted 
many years of constant experiment. He finally 
discovered that by adding to the gum a certain 
proportion of sulphur, and then heating it to a 
high degree, a chemical change took place, a com¬ 
pound being formed which would remain soft and 
pliable in all temperatures, and all the year round. 
The admixture of sulphur was a grand discovery, 
and its use was of the greatest benefit, but it led to 
another discovery—that various other substances 
could be mixed with the rubber. A demand for 
cheaper goods led to an extensive cheapening pro¬ 
cess, and what passed for rubber goods, really con¬ 
tained but a small proportion of that material, the 
bulk being made up of less expensive substances, 
to materially lessen the cost. Among the things 
which have been added to increase the bulk and 
weight, are various compounds of lead; the oxide 
of lead, (litharge), and the sulphite, (galena), as 
well as other heavy mineral ingredients; coal-tar 
and lamp-black are also used to give a jet-black 
color, and increase the bulk. Farmers aud others 
who associate weight with quality in rubber boots, 
have no difficulty in finding a heavy article, but it 
is made so by the use of foreign substances. This 
adulteration impairs the quality, and boots so made 
are sure to crack after they are wori»i short time. 
In view of the poor quality of most of the boots 
made in this manner, the Candee Co. brought out 
their “ Standard Pure” boot. It will be seen that 
a boot can not be made absolutely pure, as sulphur 
must be incorporated with the rubber, to insure 
pliability in any temperature, and if the sulphur is 
not hidden by adulterative compounds, as it very 
frequently is, it will work to the surface and give 
the boots a grey or sulphurous look. But to con¬ 
tinue our description. 
After the gum is well softened aud properly 
mixed, it is run through the calender, the large 
machine to the left of the engraving, (fig. 1), where 
it passes between heavy steel rolls, steam heated, 
and being pressed into sheets of any desired thick¬ 
ness, passes to the room 
above on an endless belt 
or apron. In the next 
machine to the left, the 
rolls are engraved with 
the diamond - 6liaped 
impressions, which give 
to the soles the rough¬ 
ened surface, with 
which every one is fa¬ 
miliar. Another ma¬ 
chine gives the “orna¬ 
mental” design for shoe 
uppers. The soles and 
uppers, being thus roll¬ 
ed out and conveyed up 
stairs to the cutting- 
room, are next cut into 
the desired sizes by 
sharp, wet knives, in 
the hands of skillful 
workmen.—In another 
department the linings, 
whether of red cotton- 
net for shoes, or of a 
napped cloth for Arc¬ 
tics, or of the “ Esquimaux ” woven cloth for 
boots, are coated on one side with rubber, by pass¬ 
ing a batch of gum in company with the cloth, be¬ 
tween heated rolls, and after-being cut into various 
sizes, many thicknesses at once by dies in a drop 
press, are distributed to the hands who make up 
the boots and shoes. 
In figure 2 is given a view of the “Candee Co.’s ” 
boot-room. On either side are the boot-makers at 
work. The Esquimaux lining is first fitted over 
the tree, rubber-side out. Then the rubber vamp 
or leg is laid on, and immediately sticks fast to the 
rubber on the lining. The workman, however, rolls 
it down with a hand-roller, so as to remove any air 
that may happen to remain between the rubber and 
the lining, and to insure perfect adhesion. This is 
an important point, for if any air be left between 
the surfaces, it will expand under the heat to 
which the boots are 
often subjected, and 
will create blisters. Fi¬ 
nally the soles are put 
on, and “ rolled down ” 
in the same manner. No 
pegging or sewing is re¬ 
quired. After the boots 
are put together, they 
are placed upside down 
on cars, and rolled into 
the varnish-room. The 
common kinds oi boots 
here receive a' coat of 
varnish. The “Standard 
Pure ” boots, however, 
are not varnished. Next 
the boots are run into 
the “heater,” to be 
vulcanized, by heating 
to nearly 300°, and the 
hoots, after remaining 
a while, are then run 
out, and, being re¬ 
moved from the 
“ trees,” are convey¬ 
ed to the packing-room for examination. The 
“pure” boots come out of a grayish color, which 
afterwards turns to a whitish yellow—but the cheap 
boots are of a shiny black, and much more attrac¬ 
tive in appearance. After the heels are nailed on, 
to make doubly sure, the inspector examines every 
boot. Those that happen to be blistered, or other¬ 
wise imperfect, are punched in the top of the leg 
iu front, and are packed and sold as “seconds.” 
After packing, the cases are ready to be shipped. 
Fig. 2.—THE BOOT BOOM IN THE L. CANDEE & CO. BUBBEK WOBKS. 
