In Mr. Marconi's early arrangements, the so-called Coherer or sensitive wave-detecting appliance, to be described more in detail presently, was inserted between the base of the insulated receiving aerial and the earth, but it was subsequently found by him to be a great improvement to act upon the receiving device, not directly by the electromotive force set up in the aerial, but by the induced electromotive force of a special form of step-up oscillation transformer he calls a "jigger," the primary circuit of which was inserted in between the receiving aerial and the earth plate, and the secondary circuit was connected to the sensitive organ of the telegraphic receiving arrangements.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
Most readers are probably familiar with the term "Coherer," which was applied by Sir Oliver Lodge, in the first instance, to an electric wave-detecting device of one particular kind-viz.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
The filings do not all cling together, but certain chains are formed which afford a conducting path for the current subsequently passed through the Coherer from an external source.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming