Students or anyone wishing to retain notes on a subject will find it quite handy to have a large envelope pasted in the back of each textbook. Instead of having notes all through the book, they can be arranged in order and slipped into the envelope. If the book is accidentally dropped, the notes will not be lost.—Contributed by Harold Mynning, Chicago, Ill.
Cleaning Steel of Grease and Stains
Grease and stains can be easily removed from steel with a mixture of unslaked lime and chalk powder, by rubbing it on the steel with a dry cloth. The best proportion for the mixture, which is easily prepared, is 1 part of lime to 1 part of chalk powder. The powder should be used dry. It is kept in cans for future use and can be used over and over again.—Contributed by Loren Ward, Des Moines, Iowa.
An Electrically Ignited Flash Light for Making Photographs
The results obtained in a great many cases in trying to take pictures by flash-light are exceedingly unsatisfactory, as the expression on the faces of the people in the picture usually is strained or unnatural, due to the suspense in waiting for the flash. The following simple device avoids this difficulty because the flash is set off by means of electricity, so that the operator can control the flash from a distant point and thus be able to take the picture quite unawares to his subjects.
The construction of the device is as follows: Obtain a piece of rather heavy sheet iron, about 6 in. wide and 10 in. long. Bend this piece of iron into the form shown in the sketch, and fasten a wooden handle to it with a wood screw. Obtain a sheet of 1/8-in. sheet asbestos, the same size as the piece of sheet iron, and glue it to the inside surface of the curved piece of iron. It is best to fasten the four corners down by means of some small rivets with rather large washers under the heads next to the asbestos.
Now mount two pieces of sheet copper, 1/2 in. wide and 6 in. long, parallel with each other on the surface of the asbestos and 1-1/2 in. apart, so that their ends are even with the end of the piece of asbestos. These pieces of copper should be insulated from the piece of sheet iron, and there should be a small screw in one end of each and a small binding post mounted on the other end.
The Asbestos-Lined Tray and the Wiring Connections for Attaching to the Electric-Light Wires