Page:Popular Science Monthly Volume 90.djvu/407

 Popular Science Monthly

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��Doing Your Tire Repairing at Home with an Electric Vulcanizer

AN electric vulcanizing outfit which enables the automobile owner to make his own casing and inner-tube repairs in twenty minutes or less, has been placed on the market by a western manufacturer. It consists of a vulcanizer with a curved surface for casing and a flat surface for inner tube repairs. Repair materials pro- vided consist of Para rubber, cement, wax paper and emery cloth. The vulcanizer works on a one hundred and ten-volt electric circuit.

In repairing a cut in the casing, gasoline and the emery cloth are used to clean the damaged part. With the cut spread open, two heavy coats of cement are applied and are allowed to dry. After this the hole is filled level with small pieces of rubber gum and the repair covered with wax paper. Then the vulcanizer is ready to be attached. This is done by applying the curved portion against the repair and fastening it securely to the casing by placing a chain around the felloe of the wheel and drawing up the thumb-nuts.

After connecting the vulcanizer to the current supply, the button is pressed and the repair proceeds automatically, the electric circuit being opened when sufficient heat has been generated to prop- erly vulcanize the rubber. For extra deep or large cuts the button is pressed a second time after the vulcanizer has cooled off.

In oval : Vulcanizing the tire casing with the curved side next to the tire. Below: Vulcaniz- ing the inner tube with the flat side to the tire

��Determining the height of a spire by multiplying the reading of the instrument by one-half of the length of the spire's base

����Measuring Sloping Roofs Without Breaking Your Neck

THE instrument shown in the illustra- tion above is designed to enable a workman to determine the vertical and sloping height of a spire quickly and 'without risk.

It is placed against the sloping sides of a roof, the pivoted pointer is made level, and a basic number by which to calculate the height of the roof is immediately ob- tained. For example, the number given by the in- strument when fitted against the side of the triangle shown in the photo- graph is twenty. By multi- plying the number of feet in the base of the triangle by twenty we will immediately obtain the vertical height, or the altitude, of the triangle in inches. The angle at which the side slopes is also given, and for the triangle in the photograph, this is roughly sixty degrees. Hence it is necessary only to measure the base of a church spire and use this instrument to obtain its height. The sloping height may then be figured from the simple well-known formula for right triangles.

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