destroyers and patrol-boats may take means to effect her
capture.

III

FORERUNNERS OF THE TELEGRAPH

From Lodestone to Leyden Jar--The Mysterious "C.M."--Spark and
Frictional Telegraphs--The Electro-magnet--Davy and the Relay
System.

The thought and effort directed toward improving the means of
communication brought but small results until man discovered and
harnessed for himself a new servant--electricity. The story of
the growth of modern means of communication is the story of the
application of electricity to this particular one of man's needs.
The stories of the Masters of Space are the stories of the men who so
applied electricity that man might communicate with man.

Some manifestations of electricity had been known since long before
the Christian era. A Greek legend relates how a shepherd named Magnes
found that his crook was attracted by a strange rock. Thus was the
lodestone, the natural magnetic iron ore, discovered, and the legend
would lead us to believe that the words magnet and magnetism were
derived from the name of the shepherd who chanced upon this natural
magnet and the strange property of magnetism.

The ability of amber, when rubbed, to attract straws, was also known
to the early peoples. How early this property was found, or how, we do
not know. The name electricity is derived from _elektron_, the Greek
name for amber.

The early Chinese and Persians knew of the lodestone, and of the
magnetic properties of amber after it has been rubbed briskly. The
Romans were familiar with these and other electrical effects. The
Romans had discovered that the lodestone would attract iron, though a
stone wall intervened. They were fond of mounting a bit of iron on a
cork floating in a basin of water and watch it follow the lodestone
held in the hand. It is related that the early magicians used it as a
means of transmitting intelligence. If a needle were placed upon a bit
of cork and the whole floated in a circular vessel with the alphabet
inscribed about the circle, one outside the room could cause the
needle to point toward any desired letters in turn by stepping to the
proper position with the lodestone. Thus a message could be sent to
the magician inside and various feats of magic performed. Our own
modern magicians are reported as availing themselves of the more
modern applications of electricity in somewhat similar fashion and
using small, easily concealed wireless telegraph or