Page:Popular Science Monthly Volume 88.djvu/342

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��Details of construction of window opening device

��Two binding-posts are fastened to the back of the clock. One post is in elec- trical contact with the frame of the clock while the other is carefully insulated from it. A fiat spring is attached to the insulated binding-post and bent into such a position that the alarm key will come into contact with it as it rotates. It is not necessary to wind the alarm up com- pletely but only to give it a fraction of a turn so that in unwinding it will touch the flat spring in passing.

The apparatus should be connected up as shown in Fig. 2. One dry cell is suf- ficient to operate this device. A press button switch may be included in the cir- cuit as shown in Fig. 2. This press- button is for use when it is desired to close the window at any time other than that for which the alarm clock switch is set.

One alarm clock switch may be used to close any number of windows at the same time by simply connecting the magnetic latches on the different win- dows in series. It will, of course, be

��necessary to increase the number of cells in the battery if more than one window is to be operated.

For Conserving Heat in Steam Pipes.

AN excellent covering for steam pipes may be made from materials that are almost always available. Take some fine sawdust and screen it through a sieve to remove any foreign bodies. Prepare a thin paste of flour and water, and mix the sawdust thoroughly with this paste. With a small trowel, the mix- ture so prepared should be applied in about 5 coats to the steam pipes while they are slightly warm. Each coat should be thoroughly dry before the next is ap- plied. If the steam pipes are in an ex- posed situation, 3 or 4 coats of coal-tar should be applied after the paste has dried ; if inside a building, this water- proofing is unnecessary. Steam pipes treated with the sawdust as above lose very little heat and, in addition, the mix- ture is much cheaper than patented prep- arations.

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