FIG. 57.—Wireless key.
An anchor gap is a simple little device consisting of a hard rubber ring bearing two or three small electrodes or sparking points. It is a necessary part of the transmitting apparatus wherever a loop aerial is used. One electrode is connected to the transmitting apparatus and the other two to the opposite sides of the aerial so that the currents divide between the two halves and equalize.
FIG. 58.—Photo of wireless key.
The key is a hand operated switch which controls the electric currents passing through the transformer or coil shutting them on or off at will and so controlling the electric oscillations in the antenna to send out short or long trains of ether waves in accordance with the dot or dash signals of the Morse alphabet.
FIG. 59.—Key and aerial switch.
The key used in a wireless station is necessarily much larger and heavier than those employed in ordinary Morse line work, in order to carry the heavy currents used by the transmitter. In spite of their size and weight, however, such keys when properly designed may be handled with perfect ease.
CHAPTER IV. THE RECEIVING APPARATUS.
The receiving instruments form the most interesting and ingenious part of a wireless station. They are the ears of the wireless station. They are wondrously sensitive but yet simple and incapable of much complication. The receiving station forms an exact counterpart of the transmitter, and the train of actions taking place are the reverse of those of the latter. The purpose of the transmitter is to change ordinary electric currents into electrical oscillations and thus set up electric waves, while the receptor converts the waves into oscillations and thence into currents which are capable of manifesting themselves in a telephone receiver. The instruments necessary for receiving comprise a