If you have a 5 by 7-in. camera and wish to use some 4 by 5-in. plates, make a few simple kits to hold the smaller plates and fit the larger holders, says Camera Craft. Take two pieces of pasteboard, A and B, black surfaced if possible, and exactly 5 by 7 in. in size. The piece A will form the back of the kit and should have an opening cut in the center 4 by 5 in. in size. Paste a piece of strong black paper, C, over the under side of it to keep the plate from falling through. Cut an opening in the other piece, B, but cut it 1/4 in. shorter. This opening, being 1/8 in. shorter at each end, will retain the plate in position and cut off only that small amount of plate surface when the plate is exposed in the camera. Cut a piece of thin black cloth, D, 1 in. wide and 5 in. long. Lay it down on a piece of newspaper and coat one side with gum or mucilage. Stand the two pieces of 5 by 7 in. black cards on end together so that they will be square and true and bind the other ends with the strip of cloth so as to form a hinge. The two cards form a thickness about equal to a thick glass plate, and go in the holder in the same way. Lay one of these kits down against the ground side of the focusing screen and draw a line around, inside of the opening. This will be a guide as to just what will be secured upon the smaller plate when the kits are used.
How to Make a Miniature Stage
A good smooth box, say 8 in. wide, 10 in. high and 12 in. long, will serve the purpose for the main part of this small theater. Cut two rectangular holes, Fig. 1, one in each end and exactly opposite each other. Place a screw eye about 1/2 in. from the edge on each side of these openings. Fit an axle in the screw eyes and fasten a spool to the middle of the axle. On one of the two spools attach another smaller spool, Fig. 2, to be used as a driving pulley. Cut out the front part of the box down to a level with the top of the spools. Connect the spools with a belt made from tape about 3/4 in. wide. On this belt fasten figures cut from heavy paper and made in the form of people, automobiles, trolley cars, horses and dogs. A painted scenery can be made in behind the movable tape. The front part of the box may be draped with curtains, making the appearance of the ordinary stage, as shown in Fig. 3. A small motor will run the spools and drive the tape on which the figures are attached.
Contributed by William M. Crilly, Jr., Chicago.
A Floating Compass Needle
When a thoroughly dry and clean sewing needle is carefully placed on the surface of water the needle will float even if the density of steel is 7 or 8 times that of water. A sewing needle thus floating upon water may be used as a compass, if it has previously been magnetized. The needle will then point north and south, and will maintain this position if the containing vessel is moved about; if the needle is displaced by force it will return to its position along the magnetic meridian as soon as the restraint is removed.