(Vol. viii., p. 364.)
As no reply has yet been given to the Query of INQUIRENDO as to who was C.
M., who described in the _Scots Magazine_, vol. xv. p. 73., as long since
as 1753, the electric telegraph, and as the article itself is one of great
interest in the history of an invention which is justly considered one of
the greatest wonders of our own times, I send a transcript of it, by way of
satisfying the natural curiosity of many readers who may not have an
opportunity of consulting it in the magazine in which it originally
appeared, and also because the doing so may stimulate farther inquiry, and
lead to the discovery of its ingenious writer, C. M. of Renfrew.
"Renfrew, February 1, 1753.
"Sir,
"It is well known to all who are conversant in electrical experiments,
that the electric power may be propagated along a small wire, from one
place to another, without being sensibly abated by the length of its
progress. Let, then, a set of wires, equal in number to the letters of
the alphabet, be extended horizontally between too given places,
parallel to one another, and each of them about an inch distant from
that next to it. At every twenty yards' end let them be fixed in glass,
or jeweller's cement, to some firm body, both to prevent them from
touching the earth, or any other non-electric, and from breaking by
their own gravity. Let the electric gun-barrel be placed at right
angles with the extremities of the wires, and about an inch below them;
also let the wires be fixed in a solid piece of glass at six inches
from the end; and let that part of them which reaches from the glass to
the machine have sufficient spring and stiffness to recover its
situation after having been brought in contact with the barrel. Close
by the supporting glass let a ball be suspended from every wire, and
about a sixth or an eighth of an inch below the ball place the letters
of an alphabet, marked on bits of paper, or any other substance that
may be light enough to rise to the electrified ball, and at the same
time let it be so contrived that each of them may reassume its proper
place when dropt. All things constructed as above, and the minute
previously fixed, I begin the conversation with my distant friend in
this manner:--Having set the electrical machine a-going, as in ordinary
experiments, suppose I am to pronounce the word _sir_; with a piece of
glass, or any other _electric per se_, I strike the wire _s_, so as to
bring it in contact with the barrel, then _i_, then _r_, all in the
same way; and my correspondent, almost in the same instant, observes
these several characters rise in order to the electrified balls at his
end of the wires. Thus I spell away as long as I think fit, and my
correspondent, for the sake of memory, writes the characters as they
rise, and may join or read them afterwards as often as he inclines.
Upon a signal given, or from desire, I stop the machine, and taking up
the pen, in my turn I write down whatever my friend at the other end
strikes out.
"If anybody should think this way tiresome, let him, instead of the
balls, suspend a range of bells from the roof, equal in number to the
letters of the alphabet, gradually decreasing in size from the bell _a_
to _z_; and from the horizontal wires let there be another set reaching
to the several bells; one, viz., from the horizontal wire _a_ to the
bell _a_, another from the horizontal wire _b_ to the bell _b_, &c.
Then let him who begins the discourse bring the wires in contact with
the barrel, as before, and the electric spark, breaking on bells of
different size, will inform his correspondent by the sound what wires
have been touched. And thus, by some practice, they may come to
understand the language of the chimes in whole words, without being put
to the trouble of noting down every letter.
"The same thing may be otherwise effected. Let the balls be suspended
over the characters, as before, but instead of bringing the ends of the
horizontal wires in contact with the barrel, let a second set reach
from the electrificator, so as to be in contact with the horizontal
ones; and let it be so contrived, at the same time, that any of them
may be removed from its corresponding horizontal by the slightest
touch, and may bring itself again into contact when left at liberty.
This may be done by the help of a small spring and slider, or twenty
other methods which the least ingenuity will discover. In this way the
characters will always adhere to the balls, excepting when any of the
secondaries is removed from contact with its horizontal; and then the
letter at the other end of the horizontal will immediately drop from
its ball. But I mention this only by way of variety.
"Some may perhaps think that, although the electric fire has not been
observed to diminish sensibly in its progress through any length of
wire that has been tried hitherto; yet, as that has never exceeded some
thirty or forty yards, it may be reasonably supposed, that in a far
greater length it would be remarkably diminished, and probably would be
entirely strained off in a few miles by the surrounding air. To prevent
this objection, and save longer argument, lay over the wires, from one
end to the other, with a thin coat of jeweller's cement. This may be
done for a trifle of additional expense; and as it is an electric _per
se_, will effectually secure any part of the fire from mixing with the
atmosphere.
"I am, &c.,
"C. M."
Surely among the numerous readers of "N. & Q." some one will be found to
tell us who C. M. was.