Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1877-05-16
Transmitting Photographs by Tele-
graph.

transmitted from one place to another
by the agency of the Geographic wire
but we have not yet been able to learn
anything of the means proposed to be
adopted for securing so desirable an end.
We are, however, says the British
Journal Of Photogyaphy, in position
to give details Of a method by which a
photograph may be transmitted with
the speed of thought" to any part
of the world with which the sender is
placed in electrical communication.
But this transmission is subject to
compliance with certain notifications
by which the original character of the
picture, as photograph, must be
slightly altered, although this altera-
ton is not necessarily any greater than
that to which it has to be subjected
before it meets the eye of the public
as an engraving in any of our illus
trated periodicals.
Rather more than twenty years
since, Mr.. F. c. Blackwell, the author
Of treatise on Electric Science
and other philosophical works, in
vented what he termed "the copying
telegraph BY means of this system
the very handwriting of the person
who wrote message could be trans
mitted in fac-simile to his correspond
ent, all errors in transmission being
avoided owing to the fact of the mes
sage being traced by mechanical
agency from the original document.
To render clear our description of a
method by which a photograph can be
telegraphed, it is necessary that we
should give brief account of Mr..
Bakewell's clever invention.
Promising that paper can be pre-
pared with certain chemicals (such as
a solution of prussiate of potash and
hydrochloric acid which are decom-
posed by the passage of an electric cur
rent, the decomposition resulting in a
visible mark at any or every place
where a sharp point in the electric cir
cult is allowed to touch the paper, it
will be readily comprehended that to
bring such sharp point in commune
cation with the paper so prepared is a
feat that can very easily be accom-
plished at a point distant thousands of
miles. Mr.. Bakewell's invention con-
sisted in causing the communication
to be written on tinfoil with an ink
which was Il nonconductor OF electric
ity. The letters thus written formed
on the surface of the metal number
of non-conducting marks. If, now,
this sheet of tinfoil, previously
trimmed to definite size, be wrapped
round a cylinder which will just suf-
flee to permit of its going once round;
if, further, this roller, placed in the
electric circuit, be made to rotate at
aNetinite rate of rapidity, and with
spiral or progressive motion from one
end to the other in relation to fixed
point; it will be obvious that if this
latter point be needle mounted with
sufficient elasticity to rise and fall as
it passes over the heights and hollows
of the letters which rotate underneath
its point (Which must be blunted so as
not TO Scratch), a current Of electricity
viii be transmitted to IA distance which
will be continuous only in the ratio of
the immunity enjoyed by the ground,
or tinfoil, from the breakages caused
by the constant interruption of the
nOn-Conducting ink with which the
message is written.
The drum or cylinder containing the
communication being rotated, spirally,
at one emo of the telegraph Wire, it
now remains 10 be shown how the
message is received at the other end.
\ cylinder, of precisely similar di-
mansions to that round which the
communication is to be sent, must be
ready at the receiving end of the wire,
and round this must be wrapped a
sheet OF paper prepared in the way we
have indicated. 1t. too. like the former
cylinder, must be pressed upon with a
needle-point tracer, and. like the orig
inal, it must also be made to rotate ut
a certain velocity previously deter
mined upon, and finally it, too, must
be made to move slowly from end to
end, SO that the point shall pass over
ii in a continuous line or spiral. 1t
only now remains that, all things being
ready, the clockwork be started, when
the former roller will rotate under
point which is transmitting electricity
subject To the Interruptions caused by
the letters of the message. AS the
paper on the receiving roller is travel
ing both in circular and lateral di-
rection at the same rate. 1t is evident
that every touch of the tracer on the
original communication will be rem
dered visible on the blank paper at the
other end of the wiIe. the only differ
ence being that whereas the original
communication is dark on white
ground, the message is received in
light letters on dark ground.
To transmit photograph in accord
ance with the principle here laid down,
il is first of all necessary that it be
converted into lines. With our pres
ent knowledge of electrical communi-