Page:Popular Science Monthly Volume 91.djvu/148

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��Popular Science Monthly

��A phonograph behind some convenient bushes took the place of an orchestra. Another clump of trees served to show where the fisherman's hut was supposed to stand. Such was the stage and its machinery. The audience, seated ancient fashion upon the hillside, enjoyed what was probably as lifelike a presentation of fairy- land as could be produced by human beings. — Shirley L. Seifert.

��An Experiment in Optics Using Heated Graphite

AN interesting experiment in optics may . be performed in the following manner: Take a bit of hard graphite, such as a lead pencil, and hold it in the tip of a candle flame until it is completely covered with soot. It will then appear black in the air, but lay it in some water, completely covering the lead part, and it will appear like silver. The explanation of this phe- nomenon is that the water is unable to touch the object, due to surface tension and lack of cohesion. The water then acts like an unsilvered sheet of darkened glass, reflecting the light. — Thomas W. Benson.

��Small Hand Drill Made from a Cheap Watch

IN doing some very fine repair work it was necessary to use a smaller drill than could be used in a breast drill without

���Two small clock gears used in the frame of a cheap watch to drive a small drill point

breaking. To accomplish the drilling of very small holes I made a drill driver of an old dollar watch and some parts taken

��from a discarded alarm clock. All the wheels, ring and winding stem of the watch were removed, keeping the frame intact, as shown at A. The drill chuck and drive shaft B were made from the ring bolt taken from the alarm clock. The nut C was cut on the dotted line and the knurled part used for tightening the slotted end of the bolt on the drill shank. Of course it is necessary to drill a hole and saw a slot across it in the threaded end of the bolt for the chuck jaws.

Two suitable gears were taken from the clock movement and arranged as shown in the watch frame. The bolt is filed or turned down to the dotted lines D to fit into the hole in the watch stem. A crank is attached to the driving shaft as at E. The handle for the crank is made from one of the feet on the alarm clock, the arm being cut from a piece of sheet metal.

��A Snap-Fastener for a Small Cupboard Door

AN efficient fastener for small cupboard l doors can be quickly and easily made from a brass-headed tack, a piece of soft rubber, a small piece of tin and a few small nails. Bore a hole in the edge of the door % in. in diameter and at least Y2 in. deep at the location for the fastener. Cut a piece of the soft rubber to a shape and size that will entirely fill the hole and drive the brass- headed tack into the rubber as shown in section drawing, taking care, however, that the tack is not long enough to enter the wood at the bottom of the hole.

Cut a piece of tin or other sheet metal about % in. square and form a depression in its center that will be just the size and shape of the head of the brass tack. Punch a small hole in each corner for nails.

In order to find the exact spot where the plate should be placed, open and shut the door a few times, causing the tack head to draw a mark on the door frame. At the extreme end of this mark make a shallow depression. Place the convex surface of the plate in this depression, tack it into place and it is ready for use.

���Snap-fastener placed on a cup- board door

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