This early spark coil was made by the E. Q. Williams company of Syracuse, New York, circa 1910.  It was intended for use in the ignition system of an early automobile or other gas powered engine, but coils like this were widely used in early low-power spark transmitters.  A coil very much like this one can be seen in an early ham radio station elsewhere on this site.

This coil measures 4 inches high, 4 inches wide, and 9 1/2 inches deep.  It weighs about 6 pounds.

The interior of the dovetailed oak cabinet is filled with a hard wax substance, which has kept moisture out of the coils so that this unit works as well today as it did a century ago.