69. The cases are made upon the same “former” on which the quarter-pound
rocket-cases are rolled. They consist of a piece of 70-lb. brown paper
and a piece of imperial board. The sheet of brown paper is cut into
strips, as represented in the annexed diagram, by which it will be seen
that each sheet furnishes enough paper for _six_ cases. The imperial
board should be divided, as shown in the following sketch, 112, into
twelve equal strips—thus: so that two sheets of 70-lb. brown paper and
one of imperial board will give material for one dozen cases for
five-pointed stars. The paper and board must be well pasted, and the
rolling board used unsparingly, as cases for this purpose cannot be too
strong and hard.
[Illustration:
Fig. 112.
]
[Illustration:
Fig. 113.
]
The common plan for filling these cases with composition is simply to
put them on the same settle on which quarter-pound tourbillons are
rammed, and to drive into the lower end of them about half-an-inch of
clay, very solid, and to ram in the composition upon this until it rises
to such a height as will enable the star to burn as long as the piece or
pieces with which it has to keep time. But I think a much better plan is
the following:—Procure a turned drift of box, or some _hard_ wood, about
five inches long in its straight part, with an end as represented at
fig. 113. Put a ladleful of clay into the case when it is upon the
settle (the ladle used for filling quarter-pound rockets is meant), and
drive down the clay with the conical end of the drift, by which means
you will have a hollow clay cone formed in the end of the case. Now ram
in your composition, which may be made from either of the following
formulas:—
FOR FIVE-POINTED
STARS.
No. 1.
Nitre 16 parts.
Sulphur 6 „
Meal-powder 4 „
Antimony 2 „
No. 2.
Nitre 16 „
Sulphur 8 „
Meal-powder 6 „
Antimony 4 „
No. 3.
Nitre 16 „
Sulphur 8 „
Meal-powder 4 „
Antimony 3 „
It will be best to decide first of all which of these compositions you
prefer, and to keep to that, remembering that five-pointed stars are
never used singly, but only as parts of compound pieces, and that, in
order to produce their proper effect, they ought to last just for a
certain time and no longer. By keeping to _one_ of the compositions
given above, you will be able to time them better. I cannot give any
directions for the quantity of composition to be driven in—this must
depend entirely upon the part which it is intended that the stars should
play in the piece for which they are made, and can be decided only by
actual experiment. The composition will not require to be driven very
hard.
You will by this time be beginning to wonder how a case filled in the
manner described above is to make a five-pointed star. Well, there is no
great difficulty in achieving this end. Provide yourself with a gimlet
which will make a hole about one-eighth of an inch in diameter, or
rather more; also with a pair of compasses the legs of which can be
secured at certain distances from one another. Let the points of the
compasses be exactly such a distance apart that they will represent
_one-fifth of the exterior circumference_ of the case—that is, so that
they will exactly go round the case in five strides, finishing at the
point from whence they started. When you have thus adjusted your
compasses, make them perform their five-stage journey _round that part
of the case inside which is the hollow clay cone_, about half-way
between the point and base of the cone, and wherever the points of the
compasses touch, there make a mark by pressing the point into the case.
You will thus have divided the circumference of the case into five equal
parts. Now at each mark made by the compasses bore a hole gently with
your gimlet, which should be a sharp one, taking care that you only bore
through the case and the clay, and disturb the composition as little as
possible. In order to prime the case, fill the hollow at the end of it,
which was occupied by the top of the settle, with wetted meal-powder,
and when this is dry, pass across it a piece of bare quick-match, the
ends of which should be long enough to be tucked into two of the
gimlet-holes, and which will convey the fire from the priming to the
composition inside the case. Then cut some pieces of thin paper (such as
double crown) three inches wide, and long enough to go twice round the
case, and paste one of these on the case just below the gimlet-holes, so
that the paper covers up gimlet-holes, priming, match, and all, and
projects an inch and a-half or thereabouts beyond the primed end of the
case. This projecting paper serves to contain the end of the encased
match which is to connect the five-pointed star with other pieces.
The best method of fixing these stars on the frames for which they are
required is to have projecting from the frames wooden pegs of such a
size that the unprimed end of the case can be squeezed tightly over them
or glued on to them. I should have stated that when the proper amount of
composition has been inserted, a little clay should be driven on the top
of it for the sake of security, and there should be not less than
three-quarters of an inch of unoccupied case beyond this clay. Into this
unoccupied space the pegs mentioned above should be fixed.
Five-pointed star-cases must, of course, be placed horizontally, with
their primed end towards the spectators; and when fired they will, or
should, present an appearance of this kind, the burning composition
protruding its tongues of white flame through the holes made by the
gimlet.
In your anxiety not to disturb the composition with the gimlet, do not
run into the other extreme, and leave the _clay unbored_. And see that
there is sufficient clay beyond the point of the cone to prevent the
combustion from finding vent there.
[Illustration:
Fig. 114.
]
The object of the conical clay head to the case is that the fire may not
burn the holes larger. If the holes were simply bored through the paper
case they would be burnt much larger than they were originally made.
Nevertheless, if it be thought too troublesome to make the hollow clay
cones, as I have suggested, a very fair five-pointed star may be made by
driving in a flat end of clay, and boring just below it into the
composition.
It is possible to make the cases for five-pointed stars of iron tubing,
such as ordinary gas-tubing, about the same size in bore as the paper
cases, the manufacture of which I have described above. Half-a-dozen
iron cases, open at both ends, with the five holes drilled at equal
distances round their circumference, and about an inch from the end,
will be found very handy, because they are indestructible, can be used
any number of times, and after use have only to be laid in hot water,
and they can be washed as clean as when new. It will be necessary to tie
something round the holes while the composition is being driven in. The
ends, of course, are made with clay.
But let me here caution you to be very careful in the use of iron cases.
If quicker compositions than those given above are employed, there is
danger of the case being blown to pieces. If this should happen it would
result in the most serious injury to any one who might be in its way.
And therefore it will be advisable, if you think of using iron cases, to
fire your experimental five-pointed star at a great distance from where
you stand, taking care that no one is near it. It will probably go well;
but there is a risk attending the use of iron cases which makes them
less safe than those made of paper and board.
I trust that these directions will enable you to prepare a satisfactory
five-pointed star.
It now remains for me to furnish you with some designs for exhibition
pieces, and to describe the manner in which they are to be made up.