A paper glider is an interesting and useful toy that can be made quickly; it may be used out of doors, but occasions when weather conditions make it necessary to remain indoors are especially good for this form of pastime. The glider shown in the sketch was worked out after considerable testing. With a toss it travels 20 to 30 ft., on a level keel, with a message slipped behind a pin, as shown in the upper sketch. The inventive boy may devise many play uses for the glider in tournaments, competitions, and for “military” flights, in which the “drivers” of the devices may “annihilate armies.” Practical use of the toy was made in a series of air-current tests.
The Glider will Travel 30 Feet, Carrying a Message, if Carefully Made
The glider is made as follows: Fold a piece of paper, 10 by 15 in., lengthwise, and mark the outline shown at the left upon it. The dimensions should be followed carefully. Measure first from the end A to the point B, and then draw the slanting line to D, at an angle of 45°. Mark the width to E, and measure the other distances from A and at the middle, to determine the curve of the edge. Mark the dotted lines extending from D, which are guides for the folding of the paper to form the glider, as shown in the lower sketch. Curl the points under the side so that the line FD comes to the position DG, and pin them to the corners H, as shown in the lower sketch. The glider is tossed by holding it between the thumb and forefinger at the middle of the fold underneath it.—S. R. Edwards, Seattle, Wash.
Cleaning a Clock with Kerosene Fumes
A simple way of cleaning a clock is as follows: Remove the pendulum and procure a ball of cotton wool, about half the size of a fist. Saturate this with kerosene, and place it in a saucer, or a tin lid, in the case under the works of the clock. Close the case and leave the cotton for several days. It will then be found that the fumes from the kerosene have brought down the dust from the works; in fact, the cotton will be covered with black specks. It only remains to oil the bearings of the works, and the clock will be quite in order.—S. Leonard Bastin, Bournemouth, England.
A Reversible Photographic Developing Tank
By LAWRENCE F. CAMPBELL
One of the chief difficulties in developing plates in a nonreversible developing tank is that irregular development takes place, because the developer tends to settle more or less, depending on the time necessary for complete development. The construction of a reversible tank is a simple matter, and the cost is slight. The tank described is 3¹⁄₄ by 4¹⁄₄, in. in size, but the dimensions can be varied for other sizes of plates. The tank is a box having grooves in opposite ends for the plates. By placing the latter back to back, 12 can be developed at a time. Sheet rubber is fitted between the cover and the body of the tank, and the cover, upon being screwed down, makes a water-tight compartment of the box. The asphaltum paint used is not affected by the developer, and preserves the wood. Fixing and developing may both be done in the one tank, but it is preferable to use the tank for developing only.
Assembly Views, Showing the General Construction and Detail of the Cover