The electric current of a wireless message was too weak to work a recording device, so Marconi made use of an ingenious little instrument invented by M. Branly, called a coherer, to hitch on, as it were, the stronger current of a local battery.

The coherer was a little tube of glass not as long as your finger, and smaller than a lead pencil, into each end of which was tightly fitted plugs of silver; the plugs met within a small fraction of an inch in the centre of the tube, and the very small space between the ends of the plugs was filled with silver and nickel dust so fine as to be almost as light as air.

One of the silver plugs of the coherer was connected to the receiving wire, while the other was connected to the earth (grounded).

To one plug of the coherer also was joined one pole of the local battery, while the other pole was in circuit with the other plug of the coherer through the recording instrument.

To one plug of the coherer also was joined one pole of the local battery, while the other pole was in circuit with the other plug of the coherer through the recording instrument.

The fine dust-like silver and nickel particles in the coherer possessed the quality of high resistance, except when charged by the electric current of the ether waves; then the particles of metal clung together, cohered, and allowed of the passage of the ether waves' current and the strong current of the local battery, which in turn actuated the Morse sounder and recorder.

So Marconi invented a little device which was in circuit with the recorder and tapped the coherer tube with a tiny mallet at just the right moment, causing the particles to separate, or decohere, and so break the circuit and stop the local battery current.

As no wireless message could have been received without the coherer, so no record or reading could have been made without the young Italian's improvement.

The first message from England to France was soon followed by one to M. Branly, the inventor of the coherer, that made the receiving of the message possible, and one to the queen of Marconi's country.

The coherer has been displaced by a new device invented by Marconi, called a magnetic detector, by which the ether waves are aided by a stronger current to record the message.

The coherer was the solution.

Thus was the principle of the coherer discovered.

With the Branly coherer as the basis Marconi sought to make improvements which would result in the detector he was seeking.

By placing these plugs with their platinum terminals in circuit with a local battery the current from this local battery was given a passage through the coherer by the action of the electric waves coming through the ether.

Marconi further discovered that the most effective arrangement was to run a wire from one terminal of the coherer into the ground, and from the other to an elevated metal plate or wire.

The waves coming through the ether were received by the elevated wire and were conducted down to the coherer.

This is to the wireless telephone what the coherer is to the wireless telegraph.

Branly coherer, 204.

Code flags at sea, 24. Coherer, 203.

This condition is so singularly like a Branly or Lodge coherer (a device which led to the discovery of wireless telegraphy) as to suggest a further analogy.

The structure of brain and nerve being similar, it is conceivable that there may be present masses of such nerve coherers in the brain, whose special function it may be to receive impulses brought from without, through the connecting sequence of ether waves of appropriate order of magnitude.