Battery Carbons

These can be readily cut with a hand-saw moistened in water.

Substitute For Copper In Daniell's Battery

Brighten sheets of ordinary sheet-tin and plunge into a very weak copper-plating solution, in connection with a galvanic battery of very low quantity. In 15 or 18 hours a tenacious film of copper will have been deposited upon the tin, and the plate can then be bent in shape suitable for the battery.

A Cheap Galvanic Battery

Mr. W. M. Symons proposes a cheap but convenient galvanic battery: each of the zinc plates is 2 in. square, and covered with fustian or other fabric, outside which thick copper wire is wound to form the other plate; the exciting liquid is weak chloride of zinc. Pairs of plates thus made can be arranged in series to form a battery to give out weak currents for a great length of time.

A Simple Galvanic Battery

Take a glass tumbler, and place in the bottom a sheet of copper, having an insulated wire attached and extending out of the tumbler. Cover the copper with blue vitriol, and suspend a sheet of zinc near the top. Fill the tumbler with water. Connect the zinc and copper together for 48 hours, and the battery will be ready for use.

Exciting Liquid For Galvanic Battery

Dissolve protosulphate of iron, 20 pts., by weight, in 36 pts. of water, stir in a dilation of sulphuric acid (equal parts of acid and water.) 7 pts., and add 1 part nitric acid similarly diluted. This liquid has great energy, and disengages no deleterious fumes.

Amalgamation Of Battery Zincs

The simplest and quickest method consists in immersing the zinc in a liquid composed of nitrate of mercury and hydrochloric acid. A few moments are Sufficient for the complete amalgamation of the zinc, however soiled its surface may be. With a quart of this liquid, which costs less than 50 cents, 150 zincs can be amalgamated. The liquid should be prepared in this manner: Dissolve in warm water 200 grains NFC mercury in 1000 grains of aqua regia (nitric acid 1 part, hydrochloric acid:3 parts). When the mercury is dissolved, add 1000 grains of hydrochloric acid.

Electro-Plated Paper Or Cloth

Make a solution of nitrate of silver, and add ammonia until the precipitate formed at first is entirely dissolved. Place the paper or cloth for 1 or 2 hours in the liquid. After removing and drying, expose to a current of hydrogen gas, by which the silver is reduced to a metallic state, and the paper or fabric becomes so good a conductor of electricity, that it may be electro-plated with copper, silver, or gold in the usual manner.

Substitutes For Rubber Insulators

Ivory and guaiacum wood, which are both relatively good conductors, become nearly non-conductive if stove-dried and saturated with certain oily and resinous liquids, which close up the pores of the bodies in question, and prevent moisture from penetrating within. Other kinds of wood can be modified in the same manner.

Sawdust. of bard wood, agglutinated with blood and submitted to a considerable pressure, so as to mould it into a solid, tenacious body, is a good insulator for voltaic currents. After remaining six days in a damp cellar, it showed no galvanometric deviation.