Makers of Many Things
, and vines from which India rubber is made. The "rubber plant" which has been such a favorite in houses is one of these; in India it becomes a la
of Cancer and the Tropic of Capricorn. More than half of all that is brought to market is produced in the valley of the Ama
General R
BBER TREES
was taken has 45,000 acres of planted
bit of clay a tiny cup underneath each cut, and move on through the forest to the next tree. Sometimes they make narrow V-shaped cuts in the bark, one above another,
can sit on the windward side, for the smoke rises through the smaller hole thick and black and suffocating. The man takes a stick shaped like a paddle, dips it into the bowl, and holds it in the smoke and heat, turning it rapidly over and over till the water is nearly dried out of the rubber and it is no longer milky, but dark-colored. Then he dips this paddle
il as to become rancid unusually soon. At length, however, a consignment of them was packed in openwork baskets between layers of dried wild banana leaves and slung up on deck i
matter from cutting a narrow path and forcing one's way through a South American or African jungle. The bark of the trees
ng the thinnest possible slice at each visit. When they have almost reached the ground, they begin on the opposite side of the trunk; and by the time they have reached the ground on that side the bark on the firs
wood. A machine called a "washer" does this work. It forces the rubber between grooved rolls which break it up; and as this is done under a spray
uch like the washer, and is formed into sheets. The square threads from which elastic webbing is made may be cut from these sheets, though sometimes the sheet is wound on an iron drum, vulcanized by being put into hot water, lightly varnished with shellac to stiffen it, then wound on a wooden cylinder, and cut into square threads. Boiling these in caustic soda rem
were waterproof,-there was no denying that; but they were heavy and clumsy and shapeless. When they were taken off, they did not stand up, but promptly fell over. In hot weather they became so sticky that they had to be kept in the cellar; and in winter they became stiff and inelastic, but they never wore out. How to get rid of the undesirable qualities and not lose the desirable ones was the question. It was found out that if sulphur wa
dd only those materials that will be of service in making the rubber more easy to mould or will improve it in some way. Unfortunately, substances are often added, not
where all the different parts of the shoes are cut out. They are then put together and varnished. While still on the last, they are dipped into a tank of varnish and vulcanized-a very simple matter now that Goodyear has shown us how, for they are
h tears them to shreds, then through a sort of fanning-mill which blows away the bits of lining. Tiny pieces of iron may be present from nails or rivets; but these are easily removed by magnets. This "reclaimed" rubber is powd
e a larger versi
y U. S.
GOES THROUG
r, rolling the rubber fabric on cylinders
nds of some pencils you can see the "fin," as the glassworkers call it, where the two pieces of the mould did not exactly fit. Rubber cannot be melted and cast in moulds like iron, but it can be gently heated and softened, and then pressed into a mould. Rubber stamps are made in this way. The making of rubber heels and soles is now a large industry; hose for watering and for vacuum and Westinghouse brakes is made in increasing quantities. The making of rubb
like rubber; it may be stretched; but it will not snap back again as rubber does. It is a remarkably good nonconductor of electricity, and therefore it has been generally used to protect ocean cables, though recently rubber has been taking its place. It makes particularly excellent casts, for when it is warm it is not sticky, but softens so perfectly that it will show the tiniest indentation of a mould. It is the best kind of splint for a broken bone. If a boy breaks his arm, a surgeon can put a piece of gutta-percha into hot wate