WIRE GAUGES. Wire is made in a num ber of sizes or diameters. To designate these sizes use is made of it series of numerals each of which indicates as certain diameter in fractions of an inch where English measure is used and in millimeters where metric measure is employed. Such a series of numerically designated sizes is called a wire gauge. There are a number of such gauges in use. In England the legal gauge is the imperial wire gauge, which was estab lished by law in 1884. Previous to this time a number of wire gauges hail been employed in England, the best known of which are the Stubbs wire gauge and the Birmingham wire gauge. France and Germany have standard wire gauges based upon the millimeter. In the United States there are a number of different wire gauges, but they are nearly all precisely similar to the Roeb ling and Washburn-Moen standard. The follow ing table shows the two American wire gauges most used and the equivalents in the English legal standard: when projected into the earth or water; (2) magnetic lines of force set up in space by mag netic induction; (3) strains in the intervening dielectric or medium separating the instruments due to electro-stfaic stresses or differences of potential; and (4) radiation of electro-magnetic ves.
Di SPERS1ON iNIETtion. This i-s also known as the leakage and as the eonductivity method. In the simplest form of this arrangement four metal plates are placed in the earth or water in paral lel as shown in the diagram Fig. 1. A represents the sending station and B the receiving station; the distance separating the plates 1, 2 and 3, 4 should be at least as great as the distance be tween A and B, over which the signals are to be tramsmitted.
At the sending station the plates 1, 2 are con nected in series with a battery, 6, and a telegraph key, 5, by means of a wire. The earth eom pletes the circuit through which the current flows in the direction of the arrows. A portion of the current flowing through this circuit is dispersed through the earth, since the latter is a very good eonduetor owing to its immense cross section, and the leakage of the current takes place in form of elliptical lines, as in Fig. 2. A small