Page:Handbook for Boys.djvu/236

Rh double-throw switch being used to switch from sending to receiving.

After having connected. up the receiving instruments, the receiver is placed at the ear and the point of the detector placed on the various parts of the mineral until the signals are heard clearly. Then the tuning coil is adjusted until the signals are loudest.

The sending apparatus is set up, the key and batteries having been bought or made, and used to call some other station. The clip is put on various twins of the helix until the other station signals that the signals are loudest. The station is then ready for actual operation.

Notes