watchmaker, and by nature a genius, invented a chemical telegraph
which was capable of a prodigious activity. The instrument of Bain
resembled the Morse in marking the signals on a tape of moving
paper, but this was done by electrolysis or electro-chemical
decomposition. The paper was soaked in a solution of iodide of
potassium in starch and water, and the signal currents were passed
through it by a marking stylus or pencil of iron. The electricity
decomposed the solution in its passage and left a blue stain on
the paper, which corresponded to the dot and dash of the Morse
apparatus. The Bain telegraph can record over 1000 words a minute
as against 40 to 50 by the Morse or sounder, nevertheless it has
fallen into disuse, perhaps because the solution was troublesome.

It is stated that a certain blind operator could read the signals
by the smell of the chemical action; and we can well believe it.
In fact, the telegraph appeals to every sense, for a deaf clerk
can feel the movements of a sounder, and the signals of the
current can be told without any instrument by the mere taste of
the wires inserted in the mouth.

A skilful telegraphist can transmit twenty-five words a minute
with the single-current key, and nearly twice as many by the
double-current key, and if we remember that an average English
word requires fifteen separate signals, the number will seem
remarkable; but by means of Wheatstone's automatic sender 150
words or more can be sent in a minute.

Among telegraphs designed to print the message in Roman type, that
of Professor David Edward Hughes is doubtless the fittest, since
it is now in general use on the Continent, and conveys our