Rubber overshoes were improved at once. As they now are made, the rubber is mixed with sulphur, whiting, litharge, and several other substances. An honest firm will add 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 for this purpose, but to increase the weight and apparent value of the articles. That is why some rubber overshoes,

for instance, wear out so much faster than others.

To make an overshoe, the rubber is run through rollers and formed into thick sheets for soles and thinner sheets for uppers. Another machine coats with gum the cloth used for lining and stays. Rubber and rubber-lined cloth go to the cutting-room, 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 merely left in large, thoroughly heated ovens for eight or ten hours. The rubber shoe or boot is now elastic, strong, waterproof, ready for any temperature, and so firmly cemented together with rubber cement that it is practically all in one piece.

During the last few years there have been frequent calls from various charities for old rubber overshoes, pieces of rubber hose, etc. These are of considerable value in rubber manufacturing. They are run through a machine which 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 powdered and mixed with the new, and for some purposes the mixture answers very well. Imitation rubber has been made by heating oil of linseed, hemp, maize, etc., with sulphur; but no substitute for rubber is a success for all uses.

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Courtesy U. S. Tire Co.
HOW RUBBER GOES THROUGH THE FACTORY
Splitting Para biscuits, mixing the rubber, rolling the rubber fabric on cylinders, and building tires on the tire machines.

There are many little conveniences made of rubber which we should greatly miss, such as the little tips put into pencil ends for erasing pencil marks. These are made by filling a mould with rubber. Rubber corks are made in much the same manner. Tips for the legs of chairs are made in a two-piece mould larger at the bottom than at the top, and with a plunger that nearly fits the small end. Often on chair tips and in the cup-shaped eraser that goes over the ends 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 rubber tires for automobiles and carriages is an important industry. The enormous and increasing use of electricity requires much use of rubber as an insulator. Rubber gloves will protect an electrical workman from shock and a surgeon from infection. Rubber beds and cushions filled with air are a great comfort in illness. Rubber has great and important uses; but we should perhaps miss quite as much the little comforts and conveniences which it has made possible.