A fused mixture of silicates of various oxides. It is of extremely varied composition and its electric constants vary greatly. Many determinations of its specific resistance have been made. For flint glass at 100° C. (212° F.) about (2.06E14) ohms –at 60° C (140° F.) (1.020E15) (Thomas Gray) is given, while another observer (Beetz) gives [...]

A suspension used for ships’ compasses and sometimes for other apparatus. It consists of a ring held by two journals, so as to bc free to swing in one plane. The compass is swung upon this ring, being placed concentrically therewith. Its journals are at right angles to those of the ring. This gives a [...]

A special kind of brass, with a high percentage of copper, used to make objects which are to be gilded by electrolysis.

The deposition of gold by an electric current, or electrolytically in the electroplating bath.

An alloy of copper, 2 parts, nickel, 1 part, and zinc, 1 part. Owing to its high resistance and moderate cost and small variation in resistance with change of temperature, it is much used for resistances. From Dr. Mathiessen’s experiment the following constants are deduced in legal ohms: Relative Resistance (Silver = 1),      13.92 Specific [...]

A secondary or storage battery. (See Battery, Secondary.)

Any apparatus for maintaining an electric current. It may be as regards the form of energy it converts into electrical energy, mechanical, as a magneto or dynamo electric machine or generator; thermal, as a thermo-electric battery; or chemical, as a voltaic battery; all of which may be consulted.

The positive plate in a voltaic couple, or the plate which is dissolved; generally a plate of zinc. Synonyms–Positive Plate–Positive Element.

Sealed tubes of glass containing highly rarefied gases, and provided with platinum electrodes extending through the glass tightly sealed as they pass through it, and often extending a short distance beyond its interior surface. On passing through them the static discharge luminous effects are produced varying with the degree of exhaustion, the contents (gas), the [...]

Friction gear in which the component wheels are pressed against each other by electromagnetic action. In the cut, repeated from Adherence, Electro-magnetic, the magnetizing coil makes the wheels, which are of iron, press strongly together.