Page:Popular Science Monthly Volume 91.djvu/652

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��Popular Science Monthly

��A Bracing for an Iron Pipe Fence Post

��THE illustration shows how a fence, the posts of which were ordinary iron pipe, was braced with a bent piece of the same sized pipe so as to stand a severe

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��A curved post brace set in concrete to make a solid support for stretching wire tightly

pull when the wire fencing was stretched on it. The brace and the posts were filled with cement, and the ring was inserted in it. The ring was shaped from a piece of heavy, flat wrought iron, which had enough shank to fit solidly into the pipe. The bases for the posts were built first and the remainder of the concrete work was left until later on, so that should any cracks develop along the edge of the post base they could be easily located and remedied. — James M. Kane.

��Attaching Linoleum to a Cement Floor

A GOOD cement for attaching linoleum to a cement floor may be made as follows: Manila gum 15 parts, brown rosin 20 parts and thick turpentine 45 parts, all by weight. "Pulverize the rosin and gum and heat until melted; then thin out with denatured alcohol, using 20 parts.

��Casing for Carrying Tube Cements Without Damage

HAVING trouble keeping the rubber cement tubes in the tool bag of my bicycle clean, I devised the tube-carrying case shown in the illustration. It consists of a brass tube about 1 in. longer than the cement tube and a little larger in diameter, with one end plugged and the other corked. — Axel H. Johnson.

���Drasstube-^ Cork'

Small brass case in- closing tubt cement

��A Silver-Plating Bath and How to Use It

THE most important attribute for the amateur plater to cultivate is caution. He is working with some of the most deadly poisons known to chemistry. He should not inhale the fumes given off in mixing solutions and should not get these solutions on his hands or clothing. No vessel employed in plating should be used for any other purpose. •

The electric current for plating should be supplied by some form of steady current battery, giving low voltage and high amperage, such as the Edison primary, Bunsen, or Fuller cells. The cells of the battery should be connected in parallel. The current must not be above two volts. For the anode, purchase a sheet of pure silver from a jewelry supply house. The sheet surface should contain from 1 to 4 sq. in. Such a plate 1/32 in. thick will cost from 75 to 90 cents. The position of the anode should be adjustable; so that more or less of its surface can be immersed, and so that it may be moved toward or away from the article being plated.

A pair of heavy wires should be provided, long enough to reach across the top of the plating tank. When placed in position the wire carrying the anode is connected with the carbon of the battery, and the one carrying the article to be plated is connected with the zinc. Cut several lengths of No. 14 or No. 16 copper wire; bend into a hook at the top, to hang on the rod connected with the zinc, and long enough to reach to the bottom of the tank. These are called "slinging wires," being twisted around the work suspended in the solution.

The next operation is to mix the solutions. Only pure chemicals should be used. Grad- uates, mixing vessels, evaporating dishes, mixing rods, etc., must be chemically clean. Use glass rods or tubing for stirring rods.

The nitrate of silver bath is made by dissolving pure scrap silver in a 25 per cent nitric acid solution. After the solution has been evaporated, the resultant crystals are dissolved in two quarts of distilled water. In another vessel, mix 1 oz. of potassium cyanide crystals in water, and add this slowly to the silver nitrate solution. Enough of the two solutions have been mixed when a precipitate forms. The liquid should be poured carefully from the material in the bottom, which is silver cyanide. This precipitate should be thor- oughly washed in pure cold water.

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