was discontinued.  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.

In sending the message from one side of his father’s estate at Bologna to the other the young inventor used practically the same methods that he uses to-day.  Marconi’s transmitting apparatus consisted of electric batteries, an induction coil by which the force of the current is increased, a telegrapher’s key to make and break the circuit, and a pair of brass knobs.  The batteries were connected with the induction coil, which in turn was connected with the brass knobs; the telegrapher’s key was placed between the battery and the coil.  It was the boy scarcely out of his teens who worked out the principles of his system, but it took time and many, many experiments to overcome the obstacles of long-distance wireless telegraphy.  The sending of a message across the garden in far-away Italy was a simple matter—­the depressed key completed the electric circuit created by a strong battery through the induction coil and made a spark jump between the two brass knobs, which in turn started the ether vibrating at the rate of three or four hundred million times a minute from the tin box on top of a pole.  The vibrations in the ether circled wider and wider, as the circular waves spread from the spot where a stone is dropped into a pool, but with the speed of light, until they reached a corresponding tin box on top of a like pole on the other side of the garden; this box, and the wire connected with it, caught the waves, carried them down to the coherer, and, joining the current from the local battery, a dot or dash was recorded; immediately after, the tapper separated the metal particles in the coherer and it was ready for the next series of waves.

One spark made a single dot, a stream of sparks the dash of the Morse telegraphic code.  The apparatus was crude at first, and worked spasmodically, but Marconi knew he was on the right track and persevered.  With the heightening of the pole he found he could send farther without an increase of electric power, until wireless messages were sent from one extreme limit of his father’s farm to the other.

It is hard to realize that the young inventor only began his experiments in wireless telegraphy in 1895, and that it is scarcely eight years since the great idea first occurred to him.

After a year of experimenting on his father’s property, Marconi was able to report to W.H.  Preece, chief electrician of the British postal system, certain definite facts—­not theories, but facts.  He had actually sent and received messages, without the aid of wires, about two miles, but the facilities for further experimenting at Bologna were exhausted, and he went to England.