Page:Popular Science Monthly Volume 91.djvu/309

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Popular Science Monthly


��such cameras are generally equipped with two small spirit levels placed at right angles to one another. These are neither ac- curate nor easily read. At best the adjust- ment of two right angle levels on top of three legs is a slow process. The civil engineers recognize this difficulty and make their surveying instruments adjustable to the level positive by means of four screws instead of three. One of the camera men has attached to his tripod-head a very simple leveling device that anyone can adjust without loss of time. It consists of a brass tube rigidly attached to the under side of the tri- pod-head. The brass tube is about \ x /l in. in diameter and 8 in. long and has cut in its lower extremity some win- dow-like apertures through which the operator can observe the position of the plumb-bob hanging from the center of the upper end of the tube. The ease and rapidity of adjustment of the camera to level position by observation of the plumb is self-evident.

To those who care to put such a device on their cameras the following suggestions and illustration may be help- ful. The openings at the lower end of the tube should be large enough to permit the operator to see the plumb-bob easily and determine whether or not it is hanging in the center line or axis of the tube. The plumb-bob may be a straight piece of wire hanging freely from a ring support, which must be placed in the exact center of the upper end of the tube ; but even if a small plumb-bob terminal is used for the sake of appearance, the support should be a wire so that it will not be likely to foul as would a string or chain if the apparatus should be inverted. — T. B. Lambert.

���Tube enclosing the plumb-bob

��A Substitute for a Shoe Horn in an Emergency

ONCE when I had been in swimming I found myself without a shoe horn, but a friend showed me a little trick that supplied my need. Simply fold your hand- kerchief two or three times and lay it in the shoe at the heel, holding one end of it. As you press your heel down into the shoe

��gradually draw on the end of the hand- kerchief, and when the heel is nearly all the way down draw out the improvised horn. The shoe will slip on the foot easily. — A. A. Kelly.

��Preserving Surfaces from Which the Paint Has Worn Off

THERE are sometimes places on the exterior of a house where the paint gets worn off and which cannot be re- touched without making a "botch job" of it owing to the difficulty of mixing the new paint to match the adjoining color which has faded. To preserve the wood in such spots until the house can be repainted, apply two coats of linseed oil with a rag. This will improve the appearance also.

��Repairing a Worn Plunger in an Automobile Oil-Pump

FREQUENTLY the cause of an engine heating up rapidly can be traced to a faulty oil-pump. This trouble was en- countered in one of the cars in our garage and upon examination it was found that



���Cap to lengthen worn oil-pump plunger

��*_ bronze cap the oil-pump Tffroi* PLJJNGER plunger was badly worn. This prevented it from deliver- ing the maximum amount of oil to the various bearings. The drawings clearly illustrate the cause of the trouble. The constant rubbing of the hardened cam against the some- what softer pump-plunger caused the plunger to wear rapidly. This wear de- creased the stroke of the plunger.

The repair was effected by providing a bronze cap to the plunger ; first to bring the stroke of the pump back to its original dimensions and secondly to provide adjust- ment against wear. A shoulder was turned at the top part and a small thread cut on it. The cap was made from a cylindrical bar of bronze and was bored out and threaded on the inside to fit the threaded portion on the plunger. — Adolph Kline.

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