The Sun.
London, England, 1868-02-17 00:00:00

NILITAR Y TELEGRA HIS.

The manner in which the Abyssinian expedition has;
oeen supplied with telegraph equipments seems to reflect
much credit on the Engineers' staff. Great saving of
time is effected by these means, whilst the cost of com-
munication with distant outposts is very considerably
decreased. A fixed line of telegraph is in itself simple
and readily manipulated, but we notice that a somewhat
original application has arisen in the form of " a flying
telegraph," by which term we understand a line capable
of following an army in its march, and to be actually used
on a battle-field. The importance of a ready means of
conveying orders from headquarters cannot be overrated.
For this purpose, forty -flue miles of Hooper's insulated
wire have been sent out, and it may be interesting tc
notice a few of the specific requirements of such a telegraph.
Being part of the military train, it must necessarily he
capable of being moved at a moment's notice, easily
erected, and readily transferable from one place to another
No fixing or burying in trenches is admissible—the wire
must be laid on the open ground. Mr. Hooper's wire is
strikingly adapted for this last condition on account of its
known capability for sustaining exposure to high tempe-
ratures without injury, and also from its being capable of
resisting a considerable amount of mechanical violence.
Experiments made at Chatham by the Royal Engineers,
under the direction of Captain Stotherd, have resulted in
chewing that heavy pieces of artillery may pass over this
wire without producing the slightest injurious effect, and
probably troops might be marched without risk over lines
of telegraph route where the Hooper wire was laid.

The results of the working of Professor Sir Charles
Wheatstone's cryptograph will be very instructive, as well
as important, as this or some such instrument appears to
be a great desideratum in military telegraphs. If an enemy
gained possession of a telegraph station, it can be readily
understood what awkward disclosures or what inimical
uses might occur ; as indeed, we have at least one very re-
markable instance in the American war. In the crypto-
graph are two circles of alphabets, one of which is set as
a key to the other, which key can be varied day by day,
or even message by message, and in this way can only
be intelligible to those for whom it is intended, and who
are previously informed of the arrangement to be used.
The message by this means will neither be known at the
telegraph stations by transmitter nor receiver, and the
strictest privacy is thus secured. By setting both alpha-
betical circles in conformity, ordinary messages can bo
transmitted.
During the Crimean hostilities a telegraph line was laid
between Varna and Balaklava, and Lord Lyons is said
to have considered that the war was considerably shortened
by the rapid communication thus afforded. Whilst pre-
parations were being made for the Abyssinian expedition,
it was urged that a line of telegraph, either along the
shores of the Red Sea or a submerged wire, would be of
immense service, and we canseenoreasonwhysuch a course
should not be prepared for, if not indeed immediately
adopted ; for the outlay would be very small compared
with the saving of expense, if the operations of such a
telegraph tended to reduce, by no more than two or three
months, the duration of the war. At least a great deal
of anxiety might be avoided by such means, as we notice
that the Malta-Alexandria cable has broken down, and
communication is therefore arrested through this channel.