at 4 P.M.,
and Edison telegraphed it to his patent agent, who immediately drew up
the specification, and at nine o'clock next morning cabled it to London.
Before the inventor was out of bed, he received an intimation that
his patent had been already deposited in the British Patent Office. Of
course, the difference of time was in his favour.

When Edison arrived at the laboratory in the morning, he read his
letters, and then overlooked his employees, witnessing their results and
offering his suggestions; but it often happened that he became totally
engrossed with one experiment or invention. His work was frequently
interrupted by curious visitors, who wished to see the laboratory and
the man. Although he had chosen that out-of-the-way place to avoid
disturbance, they were never denied: and he often took a pleasure in
showing his models, or explaining the work on which he was engaged.
There was no affectation of mystery, no attempt at keeping his
experiments a secret. Even the laboratory notes were open to inspection.
Menlo Park became a kind of Mecca to the scientific pilgrim; the
newspapers and magazines despatched reporters to the scene; excursion
parties came by rail, and country farmers in their buggies; till at last
an enterprising Yankee even opened a refreshment room.

The first of Edison's greater inventions in Menlo Park was the
'loud-speaking telephone.' Professor Graham Bell had introduced his
magneto-electric telephone, but its effect was feeble. It is, we
believe, a maxim in biology that a similarity between the extremities
of a creature is an infallible sign of its inferiority, and that in
proportion as it rises in the scale of being, its head is found to
differ from its tail. Now, in the Bell apparatus, the transmitter and
the receiver were alike, and hence Clerk Maxwell hinted that it would
never be good for much until they became differentiated from each other.
Consciously or unconsciously Edison accomplished the feat. With the
hardihood of genius, he attempted to devise a telephone which would
speak out loud enough to be heard in any corner of a large hall.

In the telephone of Bell, the voice of the speaker is the motive power
which generates the current in the line. The vibrations of the sound may
be said to transform themselves into electrical undulations. Hence the
current is very weak, and the reproduction of the voice is relatively
faint. Edison adopted the principle of making the vibrations of