** Homemade Magnifying Glass [397]

A very good magnifying glass can be made from an ordinary incandescent lamp of about 16-cp. size which has been rendered useless by being burned out or having the filament broken.  Grind or break off the tip end of the globe and fill with water.  Put in clear water and plug or cork up the hole.

** Trailer for a Bicycle [397]

[Illustration:  Fig. 1; Trailer Attached to a Bicycle]

Instead of using a seat on the handlebars or frame of a bicycle for my little girl, I made a trailer, as shown in Fig. 1, to attach to the rear axle.  I made it from old bicycle parts.  The handlebars, which form the back of the seat, fasten into the seat post of an old bicycle attached to the trailer axle.  The trailer is attached to the rear axle of the bicycle with two arms or forks, on the ends of which are two forgings, formerly used on the rear ends of a bicycle frame, brazed in, and one of the tube projections cut off from each to make a hook, as shown in Fig. 2.  The piece marked E shows one of these forgings or hooks in section.  The original axle of the bicycle was removed and one 1-5/16 in. longer supplied, which was turned below the threads for clearance, as shown at A. A washer, D, with a hexagon hole was fitted over the regular nut C, on the axle, and filed tapering so the forging or hook E, on the trailer attachment, could be kept in position.  The washer F is held tightly against the hook by pressure from a spring, G. The spring is held in place by a small nut, H, and cotter pin, 1.  This attachment makes a flexible joint for turning corners.  When turning from right to left the left hook on the trailer fork stays in

[Illustration:  Fig. 2-The Hook in Position]

position, while the right hook pushes the washer F outward and relieves the strain on the fork.  This attachment also makes it easy to remove the trailer from the bicycle.  The washers F are pushed outward and the hook raised off the axle.  —­Contributed by John F. Grieves, Providence, R. I.

** Home-Made Telephone Transmitter [398]

The parts for transmitting the sound are encased in a covering, H, made from the gong of an old electric bell.  A round button, D, is turned or filed from the carbon electrode of an old

[Illustration:  Telephone Transmitter]

dry cell and a hole drilled through the center to fit in a binding-post taken from the same battery cell.  This button must be carefully insulated from the shell, H, by running the binding-post through a piece of small rubber tube where it passes through the hole and placing a rubber or paper washer, F, under the carbon button, and an insulating washer under the nut on the outside.  This will provide one of the terminals of the instrument.  Construct a paper tube having the same diameter as the button and with a length equal to the depth of the bell case, less 1/8 in.  Glue or paste this tube to the button so it will form a paper cup with a carbon bottom.