And in this connection we must not forget that a gap occurs between the "dark heat" groups and the hertzian group, consisting of five octaves of waves, the lengths of which have been theoretically calculated, but whose action has not yet been discovered.
"The Law and the Word"
Thomas Troward
The hertzian radiator is an appliance for acting on the ether as the siren acts on the air.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
It produces a wave in it, and it can be shown that all the parts of the above described siren apparatus have their electrical equivalents in the transmitter employed in hertzian wave wireless telegraphy.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming