Wireless Telegraphy and Telephony

 WIRELESS TELEGRAPHY 47 or sparking points. It is a necessary part of the trans- mitting 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. 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 elec- tric 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. 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.