untwisting and exposing the wires to moisture. The lead sleeve should then be slipped over one of the cable ends, and about 1 inches of the insulation on each conductor removed, the wires to be joined together being given the proper lengths so that the different splices will not be bunched together at one place, but evenly distributed over the 24 inches between sheaths. A paper sleeve is then slipped over one of every two conductors to be joined, as shown at A, Fig. 97, and after the wires of each pair in one cable are joined to those of each pair in the other cable, the twisted conductors are turned down as at B, the paper sleeves slipped over the joints as at C, and by means of the ladle hot paraffin is poured over the joints as at D until no bubbles appear in the hot liquid. The bunch of conductors is then wrapped with cotton serving, the lead pipe is placed with its center over that of the splice, and its ends which project over the two cable sheaths are hammered down and soldered to them, as at E, while the splice is still hot. The best flux for this soldering is the grease from a tallow candle.

TESTING TELEPHONE LINE

WIRES AND CABLES

Continuity Tests, for determining whether or not a line wire or cable wire is broken, are made by grounding the wire at one end of the line and with a 3-cell battery and buzzer in series and grounded at the other end, touching the remaining terminal to the wire undergoing test. If the buzzer operates, the wire is continuous; if the buzzer fails to work, the wire is broken.

Testing for Crosses between wires or between wires and cable sheath is done by means of a 3-cell battery and telephone receiver. Taking, for example, the case of a cable still upon its reel, the connections are made as in Fig. 98. N represents the near end and F the far end of the wire being tested, B the battery, and T a telephone receiver. All the wires of the cable at F are carefully separated from each other and from the lead sheath; those at N are stripped of their insulation except the one under test, and are connected together and to the lead sheath by the wire C leading to the battery. The tester rapidly taps the free binding post of the receiver with the conductor joined to

the wire undergoing test. The first tap, and perhaps the second, will produce a distinct click in the receiver, but if the wire tested is perfectly insulated no further sound in the receiver will follow the tapping. If, however, the wire is crossed with any other wire in the cable or with the sheath, every tap will be followed by a distinct click in the receiver. A partial connection caused by

FIG. 99.-A Portable Wheatstone-Bridge Testing Set

moisture in the paper insulation will be indicated by faint clicks. In the same manner other wires in the cable may be tested, care always being taken to see that the exposed ends of the wires at F are separate from each other and from the sheath.

Locating Grounds, Crosses, or Swinging Wires can conveniently be done by means of a portable