Easy Electrical Experiments And How To Make Them Fully Illustrated PDF Download

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1903 edition. Excerpt: ...of a double pointed tack. The coils should not touch each other, except at the ends. The beginning of the first coil, which was left long, forms one terminal of the rheostat. The handle forms the other terminal. Accordingly, an insulated wire about 8 inches long is bared at the ends, and one end is bent around the bolt at the center, and firmly clamped between the lower nut and the upper board. A copper washer should be: inserted between the wire and the board. The other end of this wire is left projecting from the rheostat, and is provided with a connector, as shown in the preceding chapter. This wire should be secured by a double pointed tack to the framework, but must not touch the coils on any account. By turning the wooden knob more or less coils may be placed in circuit, thus varying the resistance between the two terminals. Of course, wood is not a very safe material to use in such a piece of apparatus, because of the liability of the wires to overheat. But for an amateur who deals with small currents, the apparatus above described is very useful, CHAPTER XXXII. HOW TO DO ELECTRO-PLATING AT HOME. PART ONE. Electro-plating is the art of covering metallic bodies with a thin coating of some other metal by the aid of the electric current. The process may be explained as follows: Imagine two metal plates dipping into a solution containing some metallic salt. If a current be sent through the solution, passing from one plate to the other, the solution will be broken up by the action of the current, and a portion of the metal formerly held in solution will be deposited upon the plate where the current leaves the liquid. Thus if a copper and lead plate dip into a solution of copper sulphate, and an electric current be sent through the...