The construction of telephone lines, particularly in Jefferson, must not be considered as the mere fastening of wires to almost any kind of pole or tree simply because it was previously stated that for the sake of economy trees would be used where possible in place of regualation poles.

Wires must be placed where they will not interfere with highway traffic, or be likely to fall to the ground should upper limbs break off and strike them. The cost of such poles as will be required for street corners, etc., will be about as follows: Thirty-five foot poles $3 each ; 30 ft. poles, $2.50; 25 ft. poles. $2 ; these prices are for Western grown chestnut stock. Great care must be taken that line wires do not chafe against tree trunks, which would ground the wires on stormy days and interfere with ringing " central, " as the system selected, it will be recalled, uses a ground button for this purpose. Wires passing over roofs should be drawn tightly so that the sag will not bring them in contact with the ridge-pole. Where there is any likelihood of striking, a glass insulator must be provided, and the wires securely fastened thereto.

When the line wire is brought to the point of entrance of a building, two heavy glass insulators must be placed and the wires fastened with extra strong tie wire, and soldered to the bare ends of heavy rubber covered or okonite No. 18 wire which serve as entering leads to the house. The entering wires must be at at least 6 in. apart. After the entering wires are brought through the outer wall into the room or cellar as the case may be, they are connected to a pair of protectors which, in general design, are similar to the lightning arrestor mentioned in a previous chapter, inasmuch as they are fused against strong foreign currents, and also provided with carbon grounding blocks for the same purpose. These protectors are sometimes made of wood, but the more modern types are of porcelain and cost at wholesale 16 cents per set. The ground wire for these protectors must be of heavy rubber covered or okonite wire gauge No. 16, and the ground connection must either be made upon a water pipe or by means of a coil of wire or plate buried in moist earth, in which latter case the ground wire would pass out of the building by a third hole at least one foot from the other two. The absolute importance of proper installation of this protector should be im-pressed upon the workman. Lightning which strikes upon the wires at distant points is often the direct cause of fires in factories and dwellings a mile distant, where protectors were not provided or were neglected by the owner, carbons being poorly installed or the ground wire improperly grounded or broken unintentionally after being correctly installed.

The location of the instrument upon the wall having been decided upon, instrument wires must now be placed between that point and the protectors. Upon dry walls wire which is styled "paired brown okon-ite" may be used, and this in preference to the ordinary waxed annunciator, as it has better insulating qualities, lasts longer, and is less liable to corrosion. This wire is tacked to the woodwork with ordinary short staples or double pointed tacks, great care being taken not to place a tack over two wires or allow a tack to cut into the adjoining wire while driving it. The instrument wire should be neatly taped where it passes through walls and floors, and where iron work is passed the wires should be protected by much heavier taping or by circular loom, which is a special" ly prepared tubing used generally for the purpose" There is no objection to using tape, if generously and properly applied. Only enough tacks should be used to secure the wires to the walls. Too many tacks in-increase the probability of crosses and grounds.

In placing the instrument upon the walls the transmitter arm should be perfectly horizontal, and the transmitter at proper height for the users' lips, as continually tipping the transmitter up or down greatly affects the transmission. The ground wire from the instrument may be connected to the same ground as was used for the protector ground, but must not be connected to the protector wire before it reaches the ground connection.

In wiring cellars and damp places, a better grade of insulated wire must be used, also porcelain knobs used to keep the wires clear of moisture. It is customary in many installations to have the entering wires brought into the cellar and the protectors placed on one of the beams near the point of entrance. The instrument wires then start at the protectors and pass along the beams to the room where the instrument is, if on the first floor, and brought up through a small hole bored for the purpose. In many respects this is the best way to install, as the protectors are easy of access yet out of sight.

In the next chapter will be given a list of telephone troubles which occur in general telephone practice and which are easily cleared by the subscriber. Principally among these are the difficulties attending rundown batteries after long use and the methods of testing for same; the testing of grounds which may swing in after storms, and the maintenance of the central switchboard and the station instruments.