binding post

At the left end it is fastened to the base with a screw, A. Another screw, X, serves as one binding-post.

At the left end is a small screw, while the right end is held down by the binding-post, W.

One or two small dry cells, which have binding-post terminals are convenient C-batteries.

On starting, the switch H is turned to complete the connection between one binding-post P and the field-coils.