138
��Popular Science Monthly
��width of the seam must be added to the edges of the developed pattern. This may be added in two different ways. Add a sin- gle width on the edge of one pattern and a double width on the edge of the other pattern. The other way is to divide the three-seam widths in half and add the same allowance on each pattern, which would be one and a half times the width-of the seam. Wherever there is a corner in the seam or wire allowance the metal must be cut out or "notched" as shown in the illus- tration. This is done so that the ends of the wire or seam allowance will come together neatly.
��A Pin Inserted in a Cork to Make an Oil Dropper
IN oiling fine machinery, clocks, watches, etc., too much oil is often used. Light oil flows so freely that it is difficult to get just enough out of the spout of an oil-can and to put it in the exact spot where it is needed. A needle inserted in the cork of an oil-bottle will be found to pick up just a drop of oil. This drop will be carried on the point of the needle and can be deposited ex- actly where desired. Care must be taken not to dip the needle too deep in the oil or there will be more oil clinging to its sur- face than the single drop needed for a bearing. — W. H. Sargent.
���Picking up a drop of oil with a pin
��An Automatic Watering Tank for Poultry Yards
MANY types of automatic tanks have been invented to provide fresh clean water for .the fowls all during the day. Several of these must be tipped upside down in the process of filling.
The accompanying sketch presents a type of tank in which the water may be poured in through the top. The tank can be made of galvanized iron. A small faucet, A, is placed near the bottom so that it will open beneath the surface of the water in the dish, B. The cover must fit tightly to make an airtight joint when it is screwed down. To do this a broad shoulder is left at C so that the gasket rubber D will have a firm foundation.
��The following procedure is necessary in filling the tank: Close the faucet, A, re- move the screw cap, E, and pour the water in at the top. The lid is then replaced and
���A reservoir from which fresh water is au- tomatically supplied to the poultry yard pan
the stop-cock, A, opened. The water will run out until the level in the dish, B, comes just above the opening of the faucet.
��A Trough for Thoroughly Washing Film Negatives
A SPECIAL trough for washing nega- tives will be found a great convenience to the photographer who uses films. The trough here illustrated is nothing more than a long, water-tight box, made of galvanized sheet steel, having a drain cock fitted at the bottom of one end and with a small piece of tubing soldered at the top of the other end to hold a length of rubber tubing or
���~*" A galvanized iron washing tank for rapidly removing all traces of chemicals from films
hose for making connection with a faucet. The trough is 40 in. long, 7 in. wide and 5 in. deep.
In use, the trough is placed in a level
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