on by inventing a simple device which
transmitted the required signals. It consisted of a wheel with the
characters cut on the rim, and connected with the circuit in such a
way that the night watchman, by turning the wheel, could transmit the
signals while Edison slept or studied.

His employment at Stratford came to a grievous end. One night he
received a service message ordering a certain train to stop, and before
showing it to the conductor he, perhaps for greater certainty, repeated
it back again. When he rushed out of the office to deliver it the train
was gone, and a collision seemed inevitable; but, fortunately, the
opposing trains met on a straight portion of the track, and the accident
was avoided. The superintendent of the railway threatened to prosecute
Edison, who was thoroughly frightened, and returned home without his
baggage.

During this vacation at Port Huron his ingenuity showed itself in a more
creditable guise. An 'ice-jam' occurred on the St. Clair, and broke the
telegraph cable between Port Huron and Sarnia, on the opposite
shore. Communication was therefore interrupted until Edison mounted a
locomotive and sounded the whistle in short and long calls according to
the well-known 'Morse,' or telegraphic code. After a time the reporter
at Sarnia caught the idea, and messages were exchanged by the new
system.

His next situation was at Adrian, in Michigan, where he fitted up a
small shop, and employed his spare time in repairing telegraph apparatus
and making crude experiments. One day he violated the rules of the
office by monopolising the use of the line on the strength of having a
message from the superintendent, and was discharged.

He was next engaged at Fort Wayne, and behaved so well that he was
promoted to a station at Indianapolis. While there he invented an
'automatic repeater,' by which a message is received on one line and
simultaneously transmitted on another without the assistance of an
operator. Like other young operators, he was ambitious to send or
receive the night reports for the press, which demand the highest speed
and accuracy of sending. But although he tried to overcome his faults by
the device of employing an auxiliary receiver working at a slower rate
than the direct one, he was found incompetent, and transferred to a day
wire at Cincinnati. Determined to excel, however, he took shift for
the night men as often as he could, and after several months, when
a delegation of C