ARTHUR H. BELL

Assuming that several readers have constructed private lines, as described in the September number, a few points of instruction are here given in the clearing of trouble, which is bound to come sooner or later unless the greatest cure is taken in periodic inspections of line and instruments. The handling of telephone troubles is facilitated by a thorough understanding of the equipment in use. In a general way, however, it is likely that certain defects and faults will predominate, and herewith is given a few of the most common of these difficulties, with suggestions as to their origin and quickest methods of locating.

Cannot ring or receive a ring. Line or generator circuits open.

Can hear but cannot be heard. In such cases the trouble is usually with the battery or transmitter circuit. A careful examination of all connections therewith should be made.

Weak ringing of bells. Loose connections, bad joints in line or imperfect connections at terminals of line. Bell armature adjustment may be defective.

Hearing bad. Weak battery at the receiving end or imperfect connections. Transmitter at sending end may be defective. Faulty receiver

Noises. Loose connections in line or battery circuit. Too much battery. Bent diaphram on receiver or particles of foreign substance on the magnets.

Rings O K but cannot hear at either station. Imperfect receiver cord or broken wire in the instrument circuit.

Bell rings without cause. Swinging cross with foreign wires or jarring of instrument.

In the early days of telephony it was considered that any kind of construction was good enough for telephone work, and as a consequence telephone installations were constantly out of order. Today the reverse is the case, the very best construction is none too good, and every possible requirement in construction and equipment is carried out to the smallest details. A very little consideration of the case is required to see how necessary this is. The telephone is one of the most sensitive electrical instruments known, and as it is so sensitive, the introduction of all foreign currents on the line, either by induction or leakage must be guarded against. The telephone current as transmitted is a feeble current, and therefore leakage or undue resistance must be avoided.

Great care care should be taken to see that all contacts are bright, firm and clean. The automatic hook connections should make perfect contact and the hook spring should be powerful enough to bring the hook up to the proper position each time.

It is always safe to examine all connections when looking for trouble, especially those where wires are likely to become bent or twisted. The use of dry batteries is warranted by their cheap-nesa, ease of handling and the general satisfaction they are giving in this branch of electrical work. There are a number of good makes which will give good satisfaction for six months to a year, according to use, and at the end of that time should be replaced with a new cell. Wet batteries of the salammoniac type are as efficient as dry cells, but should be kept where breakage or freezing can do no harm, and the cells should be frequently inspected to avoid drying up and crys-talizations of zinc.

It will be found by experience that the best types of commercial receivers and transmitters seldom get out of order when carefully handled. The most prolific trouble is loose connections.