Page:Popular Science Monthly Volume 88.djvu/632

 Popular Science Monthly

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closed in either direction, right or left.

The shutter is pivoted at the lower end, and the motive power is supplied by a rubber band which draws the shutter to the left when it is released to make the exposure. The exposure is made by means of a time-fuse attached to a string which holds the shutter to the right, against the pull of the rubber band, until the fuse has been consumed, when the string is burned off and the shutter released. At that moment the picture is made. The shutter must tit tightly and must admit no light to the inside of the camera, except through the exposure slit.

When the camera has thus been com- pleted it should be covered on the out- side wdth black needle paper, to make it absolutely light-tight, and the inside of the box should be blackened with a pure black ink.

The proper length of fuse to use, so as to release the shutter after the kite has attained the maximum height, can be determined by making a trial flight with the camera attached to the kite, timing with a measured length of burn- ing fuse. A length of fuse correspond- ing witl. the length burned until the kite reaches the greatest height, is attached to the string, and the camera is now ready to be loaded with film, which is done in a dark room by the light of a ruby lamp. Films of the correct size can be obtained from a film pack, or a roll film can be cut up into pieces of the correct size. The film is laid into

���Packi/y Cut from n/bber be/fina

��Large sheave wheels can be turned out ac- curately without the use of a lathe if care is taken in adjusting the timbers and handling the gearing

��the back or cover of the camera with the dull or emulsion side towards the lens, and the cover placed on the camera.

After making sure that the shutter is in proper position for making the ex- posure, the camera can be taken out into daylight and attached to the kite. A fairly stout rubber band looped around the middle of the camera box and around one of the w^ooden struts of the kite will hold the camera securely in place. The camera should always be fastened to the kite in such a manner that it points almost straight downwards when the kite is in flight ; then the pic- lures give the impression of great height.

The kite used for taking pictures from above should be fairly large and of good construction. The box type of kite is very suitable for the purpose, and many other forms wall also prove very satisfactory. Besides the pleasure of making pictures of our familiar sur- roundings from a^ove, and the great novelty of such pictures, a kite camera can also l)e used for many practical pur- poses.

Turning Out Large Sheave Wheels Without a Lathe

IN turning out sheave wheels of large diameter, a lathe is not always avail- able. The work can be accomplished in the following manner :

Place two large timbers over the mo- tor-pit (which should be parallel to the line shaft), and put spreaders between them. Bolt the timbers together and brace them up. The sheave wheel is then swung between them, as shown in the diagram. Remove the hand-chain wheel from a 2-ton chain-block and sub- stitute a 14-inch pulley for it. Take ofif one of the lift-chain wheels and insert the square end of the lift-chain axle in the square socket previously cut in the end of the sheave wheel. Bolt down the chain-blocks with two U-bolts to a piece 12'' by 12".

A heavy steel plate is then placed across the timbers in front of the sheave wheel, on which is moimted the extra tool post-head of the lathe. With this arrangement, the speed may be reduced and sufficient power gained for prac- tical work. — H. V. Abeling.

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