_Torches_ consist of a bundle of loosely twisted threads which has been
immersed in a mixture formed of two parts, by weight, of beeswax, eight of
resin, and one of tallow. In warm, dry weather, these torches when lighted
last for two hours when at rest, and for an hour and a quarter on a march.
A good light is obtained by spacing them 20 or 30 yards apart.
Another style of torch consists of a cardboard cylinder fitted with a
composition consisting of 100 parts of saltpeter, 60 of sulphur, 8 of
priming powder, and 30 of pulverized glass, the whole sifted and well
mixed. This torch, which burns for a quarter of an hour, illuminates a
space within a radius of 180 or 200 yards very well.
The _tourteau goudronné_ (lit. "tarred coke") is merely a ring formed of
old lunt or of cords well beaten with a mallet (Fig. 10). This ring is
first impregnated with a composition formed of 20 parts of black pitch
and 1 of tallow, and then with another one formed of equal parts of
black pitch and resin. One of these torches will burn for an hour in
calm weather, and half an hour in the wind. Rain does not affect the
burning of it. These rings are usually arranged in pairs on brackets
with two branches and an upper circle, the whole of iron, and these
brackets are spaced a hundred yards apart.
[Illustration: FIGS. 9 TO 16.--VARIOUS PYROTECHNIC DEVICES.]
[Illustration: FIGS. 17.--ILLUMINATING ROCKET.]
A _tarred fascine_ consists of a small fagot of dry wood, 20 inches in
length by 4 in diameter, covered with the same composition as the preceding
(Fig. 11). Fascines thus prepared burn for about half an hour. They are
placed upright in supports, and these latter are located at intervals of
twenty yards.
The _Lamarre compositions_ are all formed of a combustible substance, such
as boiled oil,[1] of a substance that burns, such as chlorate of potash,
and of various coloring salts.
[Footnote 1: For preparation see page 9304 of SUPPLEMENT.]
The _white composition_ used for charging fire balls and 1½ inch flambeaux
is formed of 500 parts of powdered chlorate of potash, 1,500 of nitrate of
baryta, 120 of light wood charcoal, and 250 of boiled oil. Another white
composition, used for charging ¾ inch flambeaux, consists of 1,000 parts of
chlorate of potash, 1,000 of nitrate of baryta, and 175 of boiled oil.
The _red composition_ used for making red flambeaux and percussion signals
consists of 1,800 parts of chlorate of potash, 300 of oxalate of strontia,
300 of carbonate of strontia, 48 of whitewood charcoal, 240 of boiled oil,
6 of oil, and 14 of gum lac.
A red or white _Lamarre flambeau_ consists of a sheet rubber tube filled
with one of the above-named compositions. The lower extremity of this tube
is closed with a cork. When the charging has been effected, the flambeau is
primed by inserting a quickmatch in the composition. This is simply lighted
with a match or a live coal. The composition of the Lamarre quickmatch will
be given hereafter.
A Lamarre flambeau 1½ inch in diameter and 3 inches in length will burn for
about thirty-five minutes. One of the same length, and ¾ inch in diameter,
lasts but a quarter of an hour.
A _fire ball_ consists of an open work sack internally strengthened with a
sheet iron shell, and fitted with the Lamarre white composition. After the
charging has been done, the sphere is wound with string, which is made to
adhere by means of tar, and canvas is then wrapped around the whole.
Projectiles of this kind, which have diameters of 6, 8, 11, and 13 inches,
are shot from mortars.
The _illuminating grenade_ (Fig. 13) consists of a sphere of vulcanized
rubber, two inches in diameter, charged with the Lamarre white composition.
The sphere contains an aperture to allow of the insertion of a fuse. The
priming is effected by means of a tin tube filled with a composition
consisting of three parts of priming powder, two of sulphur, and one of
saltpeter. These grenades are thrown either by hand or with a sling, and
they may likewise be shot from mortars. Each of these projectiles
illuminates a circle thirty feet in diameter for a space of time that
varies, according to the wind, from sixty to eighty seconds.
The _percussion signal_ (Fig. 14) consists of a cylinder of zinc, one inch
in diameter and one and a quarter inch in length, filled with Lamarre red
composition. It is provided with a wooden handle, and the fuse consists of
a capsule which is exploded by striking it against some rough object. This
signal burns for nearly a minute.
_Belgian illuminating balls and cylinders_ are canvas bags filled with
certain compositions. The cylinders, five inches in diameter and seven in
length, are charged with a mixture of six parts of sulphur, two of priming
powder, one of antimony, and two of beeswax cut up into thin slices. They
are primed with a quickmatch. The balls, one and a half inch in diameter,
are charged with a composition consisting of twelve parts of saltpeter,
eight of sulphur, four of priming powder, two of sawdust, two of beeswax,
and two of tallow. They are thrown by hand. They burn for six minutes.
_Illuminating kegs_ (Fig. 15) consist of powder kegs filled with shavings
covered with pitch. An aperture two or three inches in diameter is made in
each head, and then a large number of holes, half an inch in diameter, and
arranged quincuncially, are bored in the staves and heads. All these
apertures are filled with port-fires.
The _illuminating rocket_ (Fig. 17) consists of a sheet iron cartridge,
_a_, containing a composition designed to give it motion, of a cylinder,
_b_, of sheet iron, capped with a cone of the same material and containing
illuminating stars of Lamarre composition and an explosive for expelling
them, and, finally, of a directing stick, _c_. Priming is effected by means
of a bunch of quickmatches inclosed in a cardboard tube placed in contact
with the propelling composition. This latter is the same as that used in
signal rockets. As in the case of the latter, a space is left in the axis
of the cartridges. These rockets are fired from a trough placed at an
inclination of fifty or sixty degrees. Those of three inches illuminate the
earth for a distance of 900 yards. They may be used to advantage in the
operation of signaling.
A _parachute fire_ is a device designed to be ejected from a pot at the end
of the rocket's travel, and to emit a bright light during its slow descent.
It consists of a small cylindrical cardboard box (Fig. 16) filled with
common star paste or Lamarre stars, and attached to a parachute, _e_, by
means of a small brass chain, _d_.
To make this parachute, we cut a circle ten feet in diameter out of a piece
of calico, and divide its circumference into ten or twelve equal parts. At
each point of division we attach a piece of fine hempen cord about three
feet in length, and connect these cords with each other, as well as with
the suspension chain, by ligatures that are protected against the fire by
means of balls of sized paper.
In rockets designed to receive these parachutes, a small cavity is reserved
at the extremity of the cartridge for the reception of 225 grains of
powder. To fill the pot, the chain, _d_, is rolled spirally around the box,
_c_, and the latter is covered with the parachute, _e_, which has been
folded in plaits, and then folded lengthwise alternately in one direction
and the other.
The _parachute port-fire_ consists of a cardboard tube of from quarter to
half an inch in diameter, and from four to five inches in length, closed at
one extremity and filled with star paste. This is connected by a brass wire
with a cotton parachute eight inches in diameter. A rocket pot is capable
of holding twenty of these port-fires.
Parachute fires and port-fires are used to advantage in the operation of
signaling.--_La Nature_.
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