Page:Popular Science Monthly Volume 90.djvu/161

 Popular Science Monthly

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��perfectly with a knife or shears; but two new coins, preferably five-cent pieces, may be used with good results for the purpose. Place one on the top and the other on the bottom of the reed where it is to be trimmed. The coins should be perfectly even, above and below. Hold them tight with thumb and finger, with the reed between. Now light a match and bum oft the end that pro- jects. Run the finger over the burnt end and take oflf all the ash. This leaves a perfectly smooth round edge. — W. C. Loy.

Gluing Leather, Cloth, and the Like to Metal Surfaces

WHEN undertaking to glue leather, cloth, labels, etc., on metal, it may be difficult to get the articles to stick. Where it is possible to completely wrap the metal, the following is a good plan:

Cut a piece of print or newspaper, wide enough to go a little more than twice around the metal. Paste this up, allow it to soak a moment, then wrap it tightly around the metal, pasted side in. In drying, the paper contracts and pulls itself so tight as to form almost a part of the metal itself, which is then ready for use. If this plan is not practicable, try this:

To 3 parts liquid glue add i part glycerin. Glue up the leather, cloth or labels with this preparation and apply directly to the metal. The glycerin prevents the glue from becoming perfectly dry by absorption or evaporation, holding the labels, etc., to the metal by capillary attraction.

��Thawing Frozen Water-Pipes with an Electric Current

WHERE alternating current is avail- able, frozen pipes may be thawed by the use of a special transformer that has a large waste of magnetic energy, or with a choke-coil in series with each coil of an ordinary transformer. The secondary volt- age is usually low, but the current is high. The large magnetic leakage, or the choke-coils, permits the secondary of such a transformer to be short-circuited for several moments without injury. The piece of frozen pipe is made a part of the secondary circuit, the primary terminals of the transformer are connected with the lighting circuit, and the voltage is adjusted until the desired current through the pipe is obtained. There should be the least possible resistance in the secondary circuit; in other words, the secondary leads should be of ample size and as short as possible. Connections can be made with a hydrant and a faucet in a neighboring house, or with two faucets in two adjacent houses.

Where only direct current is available, a motor-generator, or a dynamotor is neces- sary to reduce the voltage. A motor- generator is preferable, since the voltage is under better control. The volts, amperes and time required to produce running water in a frozen pipe var>' largely and ac- cording to no fixed rule. Ordinary house pipes seldom require more than 30 to 50 volts and 500 amperes.

��Making a Bin for Storing Scrap-Brass Collected from Sweepings

ABOUT railroad shopyards, machine , and car-shops there is always more or less scrap-brass and other valuable metals

lying around where it is likely to be stolen. The loss of this metal in some shops amounts to a large sum of money each

���A bin or box to prevent thieves from taking out expensive scrap-metal from the shop-yards

year. In order to provide a safe receptacle for this material the strong-box shown in the illustration may be provided. There is a hole of suitable dimensions in the end of the box, and a shelf is placed inside of the box about 12 in. in front and on both sides of it. This shelf makes the removal of

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