, 1875-08-14

it would be more restricted still, and that full
sunlight is never to be counted on in high
latitudes, and least of all at the tops of noun
tains which are often envelopsd in Clouds
Still, in tropical countries, where sunshine can
be relied on for the great majority of days in
a large number of months in the year, the
Photograph may we'll be of the greatest possible
use in places where an electric telegraph-wire
cannot be laid down, or would not be remune-
rative il it were laid down, or where it has been
cut by the enemy. 1t seems certain that dur
ing the sieges of Metz or Paris, as Mr.. Goods
points out in his valuable. lecture, the hello
graph would have rendered the use of carrier
pigeons quite needless, and would have ens-
bled the French to send news as easily into the
besieged fortresses as out of them. A hello
graph, too, has the special advantage that, by
daylight at least, the process of interchange of
messages would usually ue Invisible to any but
the persons engaged in it, since the ray which
carries the message is not easily discovered by
any one who is quite out Of the line in which it
travels. Even if lime lights or other artificial
lights had 10 be used, by transmitting the ray
through a hole in a shutter, so as to cut off all
the fringe of light around it, it might be rem
dered very unlikely to attract attention any
where except at the place to which it was COM
missiOned.
Probably the most striking use-except the
us6 in siege Operati0ns-Which will be made
of the new invention will be it's use to travel
lers, especially in a mountainous country. For
the A ps,-granting, of course, the sun,-it
will afford far more ~effectual means of commu-
n~icating between different groups of travel lers,
and between each group and the nearest
village, than they have ever yet had. During
an ascent of Mont Blanc, for instance, there
could never be the least difficulty on a sunny
day or mOonlit night in communicating at once
with Cham0uni to procure more guides, or
fresh ropes, or any other thing needful to the
climbers Even should sudden storm and
darkness come on, a very slight addition to the
travelling apparatus of the guides would enable
them to communicate Tor such trifing distances
as these by the reflection of an artificial light.
Nothing would be easier, too, than by the help
of the Morse alphabet to make every revolving
light on the coast spell out continually its own
NAME, so that there should be no possibility of
the confusion which sailors in unfamiliar seas
sometimes make between one light and another.
We are assured on the best authority that the
Morse alphabet may easily be learned, by a
particular simplifcation, in a very much shorter
time indeed than is usually taken to learn it,
and 80 thoroughly learned as to enable the
learner to use it freely himself in communicate
ing with others. If 50, no sailor who has pass
ed his examination need be ignorant of it, and
by its help he might receive as full an assur-
ance Of where he is when he comes aero So a
revolving light as the lips of a pilot who had
lived all his life within view of the light could
give him.
There is one new danger, however, which q
general familiarity with the process of light
telegraphy is likely to bring with it. Though,
of course, the dslicate adaptations of tue hello
graph,-thosa, for instance, which enable the
operator to alter the position Of the mirror
50 minutely from minute to minute as to allow
for that infnitesimal change of the position of
the sun or the moon in the heavens which each
minute brings,-Nould be quite beyond the
reach Of prisoners and c~onvicts, yet the princi-
pie is so SIMPLE, that with a bit Of ~looking-glass
or polished metal concealed about their persons,
the populations Of our prisons will certainly
find it much easier than before TO communicate
with their fellow prisoners or their friends outside.
1.-THE dOt-and-line alphabet is easy to learn, it
might be SO combined with a cypher which
may very soon become we'll known among the
dangerous ~classss, as not to be very dangerous
for the person using it. In this way the facili-
ties for conspiracy amongst the enemies Of the
law will BIZ at least as much multiplied as the
facilities for communication amongst armies or
travellers. For the very circumstance which
makes this mode of telegraphing so i'm
portant, at least as a supplement- to the
electric telegraph,-iss simplicity, and
independence of capital and labour and long