The Wonder Book Of Knowledge Part 13

_Courtesy of the B. F. Goodrich Co._]

The cultivated rubber comes practically clean, but the crude rubber "biscuits" contain more or less dirt and foreign vegetable matter which have to be removed. The rubber is softened in hot water for a number of hours and then pa.s.sed through the corrugated rolls of a wash mill in which a stream of water plays on the rubber as it is thoroughly masticated and formed into thin sheets. These sheets are taken to the drying loft. Here they are hung up so that the warm air can readily circulate through them and are allowed to remain from six to eight weeks, until every trace of moisture has been removed. The vacuum dryer is used where rubber is wanted dry in a short s.p.a.ce of time. This is a large oven containing shelves. The wet sheets of rubber are cut in square pieces, placed on perforated tin pans and loaded into the dryer, which will hold about eight hundred pounds of rubber. The doors are closed, fastened, and by the vacuum process the water is extracted, leaving the rubber perfectly dry in about three hours' time.

[Ill.u.s.tration: SPECIAL DESIGNED MACHINE FOR CUTTING RUBBER

_Courtesy of the United States Rubber Co._]

[Ill.u.s.tration: TAPPING HEVEA RUBBER TREE ON CEYLON PLANTATION

_Courtesy of the United States Rubber Co._]

[Ill.u.s.tration: SOFTENING VATS

_Courtesy of the B. F. Goodrich Co._]

After the rubber is dry, and has been tested by the chemist, it goes to the grinding mills where it is refined on warm rolls and made ready for the compounding or mixing. It is impossible to make out of rubber alone, shoes or other products that will withstand extreme changes in temperature; certain amounts of sulphur, litharge and other ingredients are necessary in combination with the pure rubber to give a satisfactory material. The gum from the grinding mills is taken to the mixing mills, where, between the large rolls, the various materials are compounded into a h.o.m.ogeneous ma.s.s. The compounded rubber goes from the mixing mills to refining mills, to be prepared for the calenders.

[Ill.u.s.tration: _Courtesy of the United States Rubber Co._]

Automobile, motorcycle and bicycle tires, belting, footwear and many other rubber articles must have a base or backbone of cotton fabric, and in order that the fabric may unite firmly with the rubber it must be "frictioned" or forced full of rubber. This is done by drawing it between enormous iron rollers, rubber being applied on its surface as it pa.s.ses through. The pressure is so great that every opening between the fibers of cotton, every s.p.a.ce between threads is forced full of rubber.

[Ill.u.s.tration: THE MILL ROOM

_Courtesy of the B. F. Goodrich Co._]

The fabric is then ready to go with the milled rubber to the various departments of the factory to be incorporated into rubber goods. The calender is also used to press rubber into sheets of uniform thickness.

How are Rubber Shoes Made?

In making footwear, the linings and such parts as can be piled up layer on layer are cut by dies, usually on the large beam-cutting machines, commonly seen in leather shoe factories. The uppers are cut by hand from the engraved sheets, while metal patterns are used on the plain stock.

The soles are cut by specially designed machines. The sheets of rubber from which the uppers and soles are cut are at this stage of the work plastic and very sticky. It is necessary on this account to cut the various pieces one by one and keep them separate, by placing them between the leaves of a large cloth book. In an ordinary rubber shoe there are from twelve to fifteen pieces, while in a common boot there are over twenty-five pieces.

[Ill.u.s.tration: MAKING RUBBER BULBS

_Courtesy of the B. F. Goodrich Co._]

The various pieces are next delivered to the making department, where they are fitted together on the "lasts" or "trees" in such a way that all the joints and seams are covered and the lines of the shoe kept exactly. Considerable skill is required to do this, as all the joints and seams must be rolled down smooth and firm to ensure a solid boot or shoe. The goods are all inspected before they are loaded on the iron cars to go to the varnishing department, where they receive the gloss which makes them look like patent leather.

[Ill.u.s.tration: MAKING STRAIGHTLINE RUBBERS]

[Ill.u.s.tration: IN THE TRUCK TIRE STOCK ROOM]

[Ill.u.s.tration: MAKING GARDEN HOSE (WRAPPED CONSTRUCTION)]

[Ill.u.s.tration: INSPECTING AUTOMOBILE INNER TUBES

_Courtesy of the B. F. Goodrich Co._]

[Ill.u.s.tration: BELT PRESS AND ROLL OF CONVEYOR BELT]

[Ill.u.s.tration: "BUILDING" WATER BOTTLES]

[Ill.u.s.tration: VULCANIZING TRUCK TIRES]

[Ill.u.s.tration: INSULATED WIRE READY FOR SHIPMENT

_Courtesy of the B. F. Goodrich Co._]

From the varnishing department the shoes are taken to the vulcanizers, which are large ovens heated by innumerable steam pipes. The shoes remain in these vulcanizers from six to seven hours, subjected to extreme heat. This heating or vulcanizing process fixes the elasticity of the rubber, increases its strength enormously and unites the parts in such a way as to make the shoe practically one piece.

The shoes next go to the packing department, where they are taken off the "lasts," inspected, marked, tied together in pairs, sorted and packed. They are then sent to the shipping department to be shipped immediately or stored in one of the s.p.a.cious storehouses.

How are Automobile Tires Made?

In making tires, the strips of fabric are built together about a steel core to form the body or carca.s.s of the tire. The beads are also added.

The side strips, the breaker strip and finally the tread are applied.

All of these pieces are sticky, and as they are laid together and rolled down by small hand rollers they adhere to each other, and when the tire is completed it looks very much like the tires you see on automobiles, but it is not yet vulcanized. The rubber is much like tough, heavy dough--there is not much stretch to it and in a cold place it would become hard and brittle.

The tire on its steel core is taken to the mold room and placed in a steel box or mold, shaped to exactly enclose it. It is then placed with many others on a steel frame and lowered into a sort of a well or oven, where it remains for a time under pressure in the heat of live steam, after which it is removed, a finished tire.

Vulcanization is simply the heating of the rubber mixed with sulphur--this causes a chemical change in the substance; it becomes tougher, more elastic and less affected by heat and cold.

This process, discovered in 1839, made rubber the useful substance it is today. The discoverer, Charles Goodyear, to whom we referred before, was never connected in any way except by name with any of the manufacturers of the present day, but his discovery was the real beginning of a great industry.

How did the Expression "Before you can say Jack Robinson" Originate?

Jack Robinson was a man in olden days who became well known because of the shortness of his visits when he came to call on his friends, according to Grose, who has looked up the subject very carefully. When the servants at a home where Jack Robinson called went to announce his coming to the host and his a.s.sembled guests, it was said that they hardly had time to repeat his name out loud before he would take his departure again. Another man, Halliwell, who has also investigated the development of the expression, thinks that it was derived from the description of a character in an old play, "Jack, Robes on."

It is also interesting to learn that the sandwiches which we all enjoy so much at picnics are so called because of the fact that an English n.o.bleman, the Earl of Sandwich, always used to eat his meat between two pieces of bread.

What is an Aerial Railway Like?

Wonderful ingenuity has been shown in contriving a means to enable people to ascend the Wetterhorn Mountain in Switzerland. The sides of the mountain are so irregular and rough in their formation that it was found impossible to build even the incline type of railway, such as is usually resorted to where the ascent to a mountain is particularly steep. So the engineers who studied the problem finally contrived two huge sets of cables, securely fastened at the top, and fixed to a landing place a short distance from the base of the mountain. Cars, holding twenty pa.s.sengers each, are carried up and down these cables, one car balancing the other, by means of a cable attached to each, which pa.s.ses around a drum at the top.

[Ill.u.s.tration: THE WETTERHORN AERIAL RAILWAY

_Reproduced by permission of The Philadelphia Museums._]

There is probably no railway in all Europe upon which travel affords more wonderful scenery than this trip, suspended in the air, up the side of the Wetterhorn Mountain, the three peaks of which are all considerably more than two and a quarter miles high.

Why are They Called "Newspapers"?