ghtened the gloom of
this depressing period was the following letter from Professor Henry,
dated February 24, 1842:--

MY DEAR SIR--I am pleased to learn that you have again petitioned
Congress in reference to your telegraph, and I most sincerely hope you
will succeed in convincing our representatives of the importance of the
invention. In this you may, perhaps, find some difficulty, since, in the
minds of many, the electro-magnetic telegraph is associated with the
various chimerical projects constantly presented to the public, and
particularly with the schemes so popular a year or two ago for the
application of electricity as a moving power in the arts. I have
asserted, from the first, that all attempts of this kind are premature
and made without a proper knowledge of scientific principles. The case
is, however, entirely different in regard to the electro-magnetic
telegraph. Science is now fully ripe for this application, and I have not
the least doubt, if proper means be afforded, of the perfect success of
the invention.

The idea of transmitting intelligence to a distance by means of
electrical action, has been suggested by various persons, from the time
of Franklin to the present; but, until the last few years, or since the
principal discoveries in electro-magnetism, all attempts to reduce it to
practice were, necessarily, unsuccessful. The mere suggestion however, of
a scheme of this kind is a matter for which little credit can be claimed,
since it is one which would naturally arise in the mind of almost any
person familiar with the phenomena of electricity; but the bringing it
forward at the proper moment, when the developments of science are able
to furnish the means of certain success, and the devising a plan for
carrying it into practical operation, are the grounds of a just claim to
scientific reputation, as well as to public patronage.

About the same time with yourself Professor Wheatstone, of London, and
Dr. Steinheil, of Germany, proposed plans of the electro-magnetic
telegraph, but these differ as much from yours as the nature of the
common principle would well permit; and, unless some essential
improvements have lately been made in these European plans, _I should
'prefer the one invented by yourself_.

With my best wishes for your success I remain, with much esteem

Yours truly
JOSEPH HENRY.

I consider this one of the most important bits of contemporary evidence
that has come down to us. Profess