Fig. 106.-Diagram Showing Wiring of Remy Magneto System for Two Cylinder Motor.

in the winding of fine wire having sufficient voltage to overcome the air gap between the points of the spark plug.

If the switch lever is turned from the position indicated so it is in contact with buttons No. 2 and B, the battery current from a set of dry cells is used to energize the primary winding, the contact breaker of the magneto serving to interrupt the battery current and the distributor serving the same purpose whether the primary current is derived from the magneto armature winding or from the battery. The external wiring of two systems of this kind is outlined at Figs. 106 and 107. The former is for a two cylinder engine, while that at Fig. 107 is the wiring plan of the same elements shown at Fig. 105.

Q. Is the spark coil always a separate unit?

A. The spark coil used with a magneto-transformer system is always a separate unit from the armature winding but it is sometimes incorporated as part of the magneto, being carried under the arch of the magneto as in the Connecticut device or at the rear end of the magneto as in the Pittsfield construction.

Q. Describe action of double ignition system using one set of plugs.

A. Sometimes when two distinct ignition means are fitted and the magneto distributor and contact breaker are the timing parts of each system it is possible to utilize but one set of spark plugs instead of the two sets which are necessary in double ignition systems of the form outlined at Fig. 100. The diagram of the wiring of a double ignition system using one set of plugs is clearly outlined at Figs. 108 and 109. The arrangement is always such that either a separate

battery contact maker is incorporated as an auxiliary to the usual form of magneto contact breaker or the magneto contact breaker itself serves to interrupt the primary current from the battery as well as that from the armature winding. In the system shown at Fig. 109 the battery contact maker is carried at the lower portion of

Fig. 109.-Wiring Diagram of Bosch Dual System Using One Set of

Plugs.

the magneto breaker box. The induction coil is combined with a switch and is a form that can be easily secured to the dash of the car. The greater portion of the coil box extends through the dash and the connections as they are made can be clearly followed by reference to the diagram.

Q. What is the "Unisparker" system?

A. This is a secondary distributor system in which a non-vibrator coil is employed in connection with a form of timer having platinum points that establishes instantaneous contact and sends just one impulse through the primary winding of the induction coil instead of a series of impulses as produced by the ordinary roller contact timer and vibrator. It is contended that the one impulse

will generate a strong enough spark to explode any charge of gas the cylinder may contain and that the short contact is very economical of battery energy because it does not require as long a period of discharge as do the roller contact forms of timers, and there is a greater period of time between the battery discharges to permit the cells to recuperate, which is an important factor when primary current generators of the dry cell type are employed. This system is not as extensively used at the present time as it has been in the past owing to rapid strides made by the magneto in popular favor.

Fig. 110.-Two-Point Ignition System for One-Cylinder Engine.

Q. What is two-point ignition?

A. Two-point ignition systems are those in which two sparks are made to occur simultaneously at separate points in the combustion chamber. A typical two-point ignition system intended for a one cylinder engine is clearly outlined at Fig 110. As will be seen one spark plug is carried over each valve of a T head engine cylinder. The coil used has two secondary terminals instead of