ugh the ether. While these
waves themselves were too feeble to operate a receiving mechanism,
they were strong enough to arrange the particles of the sensitive
metal in the tube in order, so that the current from the local battery
could pass through them. This current operated a telegraph relay which
in turn operated a Morse receiving instrument. An electrical tapper
was also arranged in this circuit so that it would strike the tube a
light blow after each long or short wave representing a dot or a dash
had been received. Thus the particles were disarranged, ready to array
themselves when the next wave came through the ether and so form the
bridge over which the stronger local circuit could convey the signal.

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. Experimenting with his apparatus on the posts in
the garden, he discovered that an increase in the height of the wire
greatly increased the receiving distance.

At his sending station he used the exciter of his teacher, Professor
Righi. This, too, he modified and perfected for his practical purpose.
As he used the device it consisted of two brass spheres a millimeter
apart. An envelope was provided so that the sides of the spheres
toward each other and the space between was occupied by vaseline oil
which served to keep the faces of the spheres clean and produce a more
uniform spark. Outside the two spheres, but in line with them, were
placed two smaller spheres at a distance of about two-fifths of a
centimeter. The terminals of the sending circuit were attached to
these. The secondary coil of a large induction coil was placed in
series with them, and batteries were wired in series with the primary
of the coil with a sending key to make and break the circuit. When the
key was closed a series of sparks sprang across the spark-gap, and
the waves were thus set up in the ether and carried the message to the
receiving station.

As in the case of his receiving station, Marconi found that results
were much improved when he wired his sending apparatus so that one
terminal was grounded and the other connected with an elevated wire or
aerial, which is now called the antenna. By 1896 Marconi had brought
this apparatus to a state of