CONDENSER.--One of these is a condenser, which, while a spark can be produced without it, is nevertheless an important element. The office of a condenser is to absorb a certain amount of current. It will be remembered that the drawing apart of the points in a conductor, produced a spark. Now in the secondary current, of the high tension system, is an _interrupter_, a mechanism that makes and breaks the circuit continuously. INTERRUPTER.--Whenever the interrupter opens the circuit, the condenser absorbs the surging current produced by the break, so that it acts like a storage battery in the system. [Illustration: Fig. 90. High Tension Circuit.] The interrupter may be made something like the mechanism of an electric bell, in which the current is interrupted as the clapper moves back and forth. By referring to Fig. 90 a comprehensive idea may be obtained of a high tension system for igniting the compressed fuel in a gasoline engine. ARRANGEMENT OF A HIGH TENSION SYSTEM.--The dynamo A, or the battery, as the case may be, is connected up with the primary coil B, by means of the circuit wires C. The secondary coil D, which is, of course, wound around the primary B, in practice, has one of its terminals E extending to what we shall call the spark plug F. The other terminal G, of the secondary coil, also extends to the spark plug F, there being, of course, a gap between the two ends of these wires in the spark plug. Now, close up to the secondary, D, is a condenser H, the terminals of which are connected up with the two wires E G, and between the condenser and the spark plug F, is the interrupter I. THE HIGH TENSION CONNECTIONS.--With this understanding of the action of the magneto, the accompanying sketch of a high tension system will be understood. The magneto A, Fig. 91, has on its armature shaft B, two distributer rings C D, which form the terminals for the two wires E F, which run out from the armature winding. C is connected by metallic contact with this shaft, and D insulated therefrom. Also, alongside of the ring D, is the interrupter wheel G which engages the finger H, and thus interrupts the circuit. Above the armature shaft, and parallel therewith, is a shaft I, turned at half the armature shaft by means of the two gear wheels J K. On the end of this shaft is a finger J, revoluble therewith, and this engages successively with four contact plates K, each plate being connected with a spark plug in the engine, assuming, of course, that there are four cylinders in the engine. [Illustration: Fig. 91. High Tension Connections.]