282
��Poptdar Science Monthly
��uprights A, A, A, and are firmly toe- nailed to them. They are further strengthened by three pieces of iron, each 6 ins. long, and i in. by 8 ins. These are bent to fit the angle of the outside of the uprights and the piece G, and are then fastened by screws to both.
More iron of the same size is used to make the guy-wire hooks, as shown in Fig. 5- Six are required to be fastened to the cross-wires as indicated. Carriage bolts are inserted through holes drilled in the end.s, and the wires are attached to these bolts. Ob\iously, the guy- wires are attached before raising the mast, and may be broken up by in- sulators as usual. No. lo or 12 gal- vanized iron wire is good for the guy- wires, the lower ends of which should be fastened to heavy stakes, trees or "dead men." A good anchor is made by burying about 3 ft. of telephone pole, with a stout wire fastened around it, some 3 or 4 feet deep (crosswise or horizontally). The guy-wires may be fastened as close as 20 ft. to the base of the mast, but should be farther away if space and conditions permit.
Since the mast is rather light, a heavy foundation is not necessary. A good foundation can be made by digging a hole somewhat larger than the mast and about 2 ft. deep, and filling it with a cinder or stone-concrete mixture, leveled off on top. Three pieces of pine, 3 ins. by 3 ins. and about l foot long, should be embedded in the concrete about 6 ins., forming a triangle the size of the inside of the base. Wlien the mast is set over these, the three uprights may be nailed to them as shown in Fig. 7, thus keeping the foot of the mast on the foundation.
A pulley should be attached to the top of the mast by means of an eye-bolt through the pole. A good half-inch nianila rope is best for the halyard. The rope should be twice as long as the mast and siiliced to prevent its pulling out at the top. This pole is very stiff, if carefully constructed, and may be picked up by the extreme ends without bending. In raising, there should be a man at each guy-wire to keep the mast straight. If it is to be near a building, a block-and-tackle may be riggetl up 011 ihe side of (he building
��and the mast raised by hauling on the top or middle. If no such conditions exist, it may be pushed up with poles in the way a telephone pole is handled. Painting, preferably with whitelead, should, of course, be completed before erecting.
The builder will find the mast much easier to construct, once he gets started, than he may at first imagine. The first mast of this type ever built has been up for some time, and has weathered se\'eral hard windstorms, in spite of the fact that the two guy-wires which carry the strain are in a line that is not more than 12 ft. from the base. — C. S. Robinson.
A Sending Condenser
A GREAT many amateurs try to use glass fruit jars of brine in a tank or pan of brine but after a trial give up this scheme because of the brush dis- charge and the bother of frequently having to replenish the water. If enough automobile lubricating oil is poured in to make a layer of about one- half inch on top of the salt solution, the evaporation and most of the brush discharge will be stopped. The inside brine acts as the inner coating of a Leyden jar, and the salt water in which the jars stand takes the place of the outer coating. The drawing shows how to connect for high or low \uhage.
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���Series connection
���Parallel connection
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