Page:United States patent 624516.pdf/4

one end of the tube j for receiving. The other end of the tube j is connected by a wire J to the inside of the box.

The aerial conductor need not be insulated as shown, but may be connected to earth through the primary of an induction-coil, the ends of the secondary of which are connected to the terminals of the receiver. This arrangement is shown in Fig. 3. The contact H′, in place of being connected to the end of tube j, is connected to the inside of the box through the primary K of an induction-coil, while the two ends of the tube j are connected to the secondary K′ of the coil. L is a condenser in a shunt across the wire leading from the tube j to the coils k′. In other respects the arrangement is the same as that shown in Fig. 1, and the parts are marked with the same letters.

What I claim is —

1. The combination of a transmitter, a receiver, an aerial conductor, a metallic box containing the receiver, earth connections to one terminal of the transmitter and to the box, an interchangeable connection from the aerial conductor either to the other terminal of receiver and a connection between the other terminal of the receiver and the box.

2. The combination of a transmitter, a receiver, an aerial conductor, a metallic box containing the receiver, earth connections to one terminal of the transmitter and to the box, an interchangeable connection from the aerial conductor either to the other terminal of the transmitter or to one terminal of the receiver, a connection between the other terminal of the receiver and the box, a relay operated by the receiver, a telegraph instrument outside the box, a connection between the box and one terminal of the relay, a connection between the box and one terminal of the telegraph instrument and a connection insulated from the box between the other terminals of the relay and telegraph instrument.

3. The combination of a transmitter, a receiver, an aerial conductor, a metallic box containing the receiver, earth connections to one terminal of the transmitter and to the box, an interchangeable connection from the aerial conductor either to the other terminal of the transmitter or to one terminal of the receiver, a connection between the other terminal of the the receiver and the box, a relay operated by the receiver, a telegraph instrument outside the box, a connection between the box and one terminal of the relay, a connection between the box and one terminal of the telegraph instrument, a connection insulated from the box between the other terminals of the relay and telegraph instrument, a coil of the insulated wire outside the box in the latter connection and a metallic covering to the insulation in connection with the box.

Witnesses:

Robert B. Ransford,

John H. Whitehead.