The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

364 THE ELECTRO-CHEMICAL TELEGRAPH.
these effects and facts; nor is it intended to claim the use of
any particular chemical solution, either separate or conjoined;
because the paper saturated with a solution of nitric acid only
will receive a communication that will not become visible, until
the paper is washed with a solution of prussiate of potash;
therefore any chemical solutions rnav be used that will produce
the best effects; and I have stated the solutions of nitric acid
and prussiate of potash as those that I have hitherto found most
effective in practical use.
It is believed to be sufficiently plain, without much explanation, that as the perforations composed in the paper successively
pass under each comb, the electric circuit will be completed,
by the points of the comb coming in contact with the roller
through such perforation, and that a corresponding period of
rapid electric pulsations will be thus communicated simultaneously to the marking style at each distant station. It is
proper to remark, that the battery in connection with each
transmitting roller, must be of proportionate strength to the dis
tance the current has to travel; and these arrangements admit
of so graduating the strength of each battery, because each
separate circuit is totally and entirely independent of any other
circuit; and each circuit is completed at the receiving station,
independent of any other station, and the communication transmitted is received and recorded at each receiving station, in the
same manner, and with the same effect, as if made with the
single acting machine first described.
All other electric telegraphs hitherto used are dependent on
the motive power of electro-magnetism for their action, and
many mechanical means have been sought or tried, whereby
to adapt this power for use, the main principle remaining the
same in all; the machines are, consequently, all designated
" Electro-Magnetic Telegraphs."
But electricity travels with a velocity capable of giving several thousand signals per minute of time; and any apparatus
composed more or less of ponderous bodies, having also to give
motion to other and similar bodies, cannot act with more than
a fraction of the velocity with which electricity travels; and
another and greater hinderance is, that, however skilful an operator may be, he can only open and close the electric circuit, in a
manner which again reduces the numerical velocity of its pulsations, and no other mode has yet effected the correct transmission of the same communication to a plurality of distant
receiving stations.
I have, therefore, in my hereinbefore described invention, re.
jected magnetism altogether; and caused the pulsations of the