Gate Fasteners
Buttons on gates or small doors are apt to become loose and then drop down, thereby allowing the gate or door to become unfastened. The ordinary button is shown at A where it is loose and turned by its own weight. If the button is cut as shown at B, it will remain fastened, even if it is loose on the screw or nail.—Contributed by A. S. Thomas, Amherstburg, Ont.
A Compensating Siphon
The homemade siphon shown in the sketch consists of two rubber corks and a glass tube with a rubber hose connected to it. The cork A is used as a bearing and support on the edge of the tank. The position of the cork B on the tube determines the distance that the mouth of the tube will be under the surface of the liquid, also to some extent the sensitiveness of the apparatus. However, the principle of the device is the buoyant effect of the water and the lever action of the rubber tube which is attached.
The End of the Pipe is Kept Just under the Surface of the Liquid at all Times
The one that I made had a tube 14 in. long, and the cork B was 1-3/4 in. in diameter, 1 in. thick, and weighed about 1/10 of a pound. The practical application of this siphon will be found in sieve tests where it is necessary to collect the residue on the bottom of the tank while drawing off the liquid at the surface, also in oil-storage tanks where it is not wished to disturb the dirt or other residue which collects on the bottom of the tank.—Contributed by James Hemphill, Jr., Duquesne, Pennsylvania.
A Polarity Indicator
Lines in a cable or the ends of connections at a distance from the battery must be tested to determine the polarity. Where a large amount of this work is to be done, as in automobile and motorboat repairing, it is necessary to have an indicator to save time. A cheap indicator for this purpose can be made of a 6-in. test tube having its ends sealed and inclosing a saturated solution of ammonium chloride (sal ammoniac) and water. The sealed ends are made by inserting a piece of wire through a cork and, after forcing this tightly into the end of the test tube, covering it with sealing wax.