The symbols and numbers
expressing the alphabet are identical with those forming the alphabet in
the Signal Book.
[Chart with code signals].
All particulars as to the machines and lanterns used in the Service, for
making these flashing signals, and the code, can be procured at W. Nunn and
Co.'s Army and Navy Lamp and Signal Works, 65, George Street East,
London, E.
Reflecting the Sun with a Mirror.--To attract the notice of a division
of your party, five or even ten miles off, glitter a bit of looking-glass
in the sun, throwing its flash towards where you expect them to be. It is
quite astonishing at how great a distance the gleam of the glass will
catch the sharp eyes of a bushman who has learnt to know what it is. It
is now a common signal in the North American prairies. (Sullivan.) It
should be recollected that a passing flash has far less briliancy than
one that dwells for an appreciable time on the retina of the observer;
therefore the signaller should do all he can to steady his aim. I find
the steadiest way of holding the mirror is to rest the hand firmly
against the forehead, and to keep the eyes continually fixed upon the
same distant object. The glare of the sun that is reflected from each
point of the surface of a mirror forms a cone of light whose vertical
angle is constant, and equal to that subtended by the sun. Hence when a
flash is sent to a distant place, the size of the mirror is of no
appreciable importance in affecting the size of the area over which the
flash is visible.
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