CHAPTER XI

INDUCTION COILS

The induction coil has always been a popular piece of apparatus with those interested in electrical science; the experiments which can be performed with its aid are very numerous. It is of considerable importance, especially in its application to such useful purposes as X ray work, wireless telegraphy and _ignition_ for gas engines. The latter has caused manufacturers to give much attention to the development of the induction coil, resulting in many refinements of design and construction.

Induction coils may be divided into two general classes:

1. Primary coils; 2. Secondary coils.

The subject of electromagnetic induction has been fully explained in