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

RONALD S ELECTRIC TELEGRAPH. 149
nication was finished. The attention of the distant observer
was called by the explosion of gas by means of electricity from
a Leyden jar.
Fig. 2. Fig. 3.
EXPERIMENTS AND DESCRIPTION OF THE APPARATUS.
Mr. Ronald has given the following additional explanations
of his invention in his work, entitled a " Description of an
Electric Telegraph, and some other Electrical Apparatus:"
In fig. 1, D is an electrical machine; B, the pith-ball electrometer; A, the screen hiding the letters on the dial behind it;
F, the gas alarum; E, the tube conveying the wires.
Fig. 2 shows the moveable dial hidden by the screen in
filg.
Fig. 3 is an enlarged drawing of the screen, with orifice and
pith-ball electrometer.
Mr. Ronald entered on the subject of the comparative merits
of wires suspended in the air and wires buried in the earth,
and arrived at the conclusion that subterranean wires were much
to be preferred, although many persons were found to object to
that plan.
He says: " The liability of the subterranean part of the apparatus to be injured by an enemy or by mischievously disposed persons has been vehemently objected to-more vehemently
than rationally, I presume to hope (as is not unfrequently the
case on these as on many other sorts of occasions). If an
enemy had occupation of all the roads which covered the wires,
he could undoubtedly disconcert my electric signs without
difficulty; but would those now in use escape? And this case
relates only to invasions and civil war; therefore let us have
smokers enough to prevent invasions, and kings that love their
subjects enough to prevent civil wars.
"To protect the apparatus from mischievously disposed per