rolled dry, and secured on the inner and outer edges with paste. After
sticking it on the case, which it may be made to fit, as in fig. 36,
pinch the top in like a choke, only tight, and tie it round with twine
or flax. For coloured rocket heads, 6/8 and upwards, the head may be
enlarged by fixing a collar round the top of the case. To make the
collar for a 6/8, roll a case on a 9/8 former, and when dry cut it into
short lengths in the lathe, as recommended for pill-boxes; if unprovided
with a lathe, saw it with a fine-toothed saw. The advantage of the
enlarged head is, that it brings the stars nearer to the rocket, and
prevents it from being top-heavy. Another way is to make the heads
tapering, and the tops conical, as in fig. 39. One part is rolled on
fig. 34, the other on fig. 35; or, a cone may be made of a circular
piece of paper, without a former. Cut the circle, along the radius, to
the centre; bend it into a cone; secure the edge with sealing-wax, and
paste paper over it to overlap the rim: snip the edge with the scissors;
paste it inside, and secure it to the other part. But the quickest way
of all is to make a long paper bag, which may be made to fit to the
greatest nicety. For this purpose take a tape-measure; or lay down, on
the edge of a strip of writing paper, 7 or 8 inches long, and 1 inch
broad, 6 inches, divided into eighths, transferred from a foot-rule.
Suppose the 6/8 rocket has a collar, which, on being measured by the
paper just alluded to, is found to be 4-2/8 inches round; add to this
3/8 for lapping over, making 4-5/8 inches. Cut a piece of imperial brown
4-5/8 broad, and as long as the case, 6 inches. Make this into a paper
bag, 2-1/8 inches broad. Be careful that the corners are perfect; a
strip of double-crown may be pasted over them. When dry, pinch the mouth
open till cylindrical, and merely allow the stars to drop in without
forcing them; this will keep the top edge of a wedge shape, fig. 37, and
answer the purpose of a cone. If the paper is thin, the bag must be made
of two thicknesses; the paper will, then, require to be 9 inches by 6;
4-3/8 of this will have to be kept dry, and the other 4-5/8 pasted.
A head, made in this way, if required to hold gold rains, or serpents,
can instantly be reduced to a cylindrical shape, by pushing the
rocket-case right up it, to the top; this will cause the corners to
stick out, like two horns; press them down, and secure them with
sealing-wax. Attach a cone, if desired.
Heads made like figs. 38 and 39 may be of three thicknesses of paper,
pasted all over.
Fig. 39 shows the manner of tying on the sticks. No variation must be
made in their lengths, and it is not advisable to alter their size. To
adapt it to the wood, however, a slight alteration might be permitted.
For instance, instead of 3/8 square, it might be (2-1/2)/8 by (3-1/2)/8,
a slight increase one way, compensated by a slight diminution the other.
It must, however, on no account, be so increased and diminished, as to
approach the shape of a lath, as such stick would vibrate, and cause the
rocket to quiver. When the heads are a paper bag of the shape of fig.
37, the stick must be tied on, as indicated by the dotted lines.
If the stick is suited to the rocket, it will, when suspended on the
finger almost against the mouth, as at f, fig. 40, lie, not quite
horizontal, but slightly sloping downward. The wood should be dry pine,
free from knots. The sticks are generally cut with a carpenter's
cutting-gauge. If the learner has a lathe he will find a 6-inch
circular saw convenient for cutting them.
For amateurs, a 6/8 rocket is a good size; large enough, and small
enough. If 5/8 and 4/8 are made, two hollow drifts will be sufficient;
for 3/8, one hollow drift. Very small rockets, 2/8, are made for
children; they are rammed solid, and a hole is pushed up them with a
bradawl.
Rockets in former times, before the present days of competition, were
charged in moulds. These were of gun-metal, bored truly cylindrical,
furnished with hinges, to open and admit the case; they were then
screwed up, and might be charged as hard as possible. Names were given
them according to the bore of the mould, that is, the external diameter
of the cases; a 4/8 was termed an ounce rocket; a 5/8, a two ounce; a
6/8 a quarter pound; a (7-1/2)/8 a half pound; a 9/8, a pound; a 12/8, a
two pound.
These names were determined by the weight of a leaden ball of the same
diameter as the bore. Now a sphere of lead, 7-1/2 inches diameter = 90
lbs., or 1440 ounces; consequently one of 15 inches = 720 lbs., similar
solids being to each other as the cubes of their like dimensions: the
latter sphere being twice the diameter from top to bottom; twice the
diameter from left to right; and twice the diameter from front to back;
2 × 2 × 2 = 8.
The external diameter of the rocket being 7-1/2 inches, the internal
would be 5 inches, and this would be a 90-pounder: hence, for an inch
rocket, we have the proportion,
oz. oz.
5³ : 1440 :: 1³ : 11·52
so that a 12-ounce, or 3-quarter-pound rocket, ought to be a trifle
above an inch.
Required the weight of a 6/8 rocket. 5 inches = 40/8.
oz. oz.
40³ : 1440 :: 6³ : 4·86
So that a 6/8 is a trifle too large for a quarter-pound.
If, conversely, we require to know the size of a half-pound, or 8-ounce
rocket,
oz. oz.
1440 : 40³ :: 8 : 3200/9
and ∛(3200/9) = ∛(9600/27) = (∛9600)/3 = 7·08
So, properly, a half-pounder is a trifle over 7/8. The names in use
enable the makers to understand each other, but they are not
mathematically correct, and are of no utility to an amateur.
The following table shows the true weight of leaden spheres, the
dimensions being taken in inches.
+--------+----------++--------+----------++--------+----------+
| Weight.| Diameter.|| Weight.| Diameter.|| Weight.| Diameter.|
+--------+----------++--------+----------++--------+----------+
| 1 dram | ·264 || 1 oz. | ·664 || 1 lb. | 1·672 |
+--------+----------++--------+----------++--------+----------+
| 2 drams| ·332 || 2 " | ·836 || 1¼ " | 1·8 |
+--------+----------++--------+----------++--------+----------+
| 4 " | ·418 || 4 " | 1·056 || 1½ " | 1·91 |
+--------+----------++--------+----------++--------+----------+
| 8 " | ·528 || 8 " | 1·328 || 1¾ " | 2·02 |
+--------+----------++--------+----------++--------+----------+
|12 " | ·604 || 12 " | 1·52 || 2 " | 2·112 |
+--------+----------++--------+----------++--------+----------+
And 2/3 of the above numbers multiplied by 8, give the correct names for
rockets in eighths of an inch.
Required the true size of a half-pounder.
1·328 × 2 × 8
------------- = 7·08.
3
A trifle above 7/8, as before stated.
A cast-iron ball 6 inches in diameter weighs 30lb.
Cast iron is about 40/63 the weight of lead.
5280 feet = 1 mile; 3280 feet = 1 kilometre.
_WHEEL AND FIXED CASES._
Wheel cases may be 5-5/8 inches long. Cut the paper, without waste, into
4 strips, each 29 inches long. Fixed cases may be 7-1/4 inches long: cut
the paper the other way of the sheet, into 4 strips, each 22-1/2 inches
long. The extra length, for fixed cases, is to allow of their being
reported; that is, filled at the end, with an inch, or more, of grain
powder, to make a bang like a squib. The cases are to be gauged to the
thickness of roman candle cases, but choked like rockets; 5/8 internal,
and 7/8 external, are a good size. Two solid drifts will be required for
wheel cases; one 5-1/2 inches long, besides the head; the other 3
inches: for the fixed cases it will be necessary to have one of 7-1/4
inches. They may be turned of box, beech, or ash; but gun-metal drifts
are best, though by no means indispensable. If they are cast in
gun-metal, they will simply require filing in the rough places. The
cases are to be rammed solid throughout, on a foot, fig. 42, turned in
one piece, with a nipple, and a pin 1/3 of a diameter thick, and just
high enough to keep the choke clear.
In all wheel and fixed cases, whatever the remainder of the fuse may be,
begin by putting in one scoop of starting fire; this, when malleted
firmly in, should fill about 3/8 of an inch in the case. The subsequent
fuse can be selected from the Tables. The choke may be protected with a
little clay, before the starting fire, like rockets, if thought
desirable: no clay is to be used anywhere else. Wheel cases containing
steel-filings are termed brilliant.
To prime the cases, very slightly damp some meal powder, by sprinkling
it with a few drops of water; mix and chop it up, or mince it, as it
were, with a knife: put a little into the mouth of the case, press the
nipple, fig. 42, into it, and work it round; this will prime the choke
and the mouth at once, still leaving the choke clear; or, paint the
choke and mouth with the sash-tool, with meal paste, just sufficient to
wet them, then plunge them into dry meal, give them a rap to shake off
the superfluous dust, and lay them by to dry.
Wheel and fixed cases need not be choked at all, but plugged 1/4 of an
inch, with plaster of paris, as directed for roman candles. When dry,
charge them by setting them flat on the block, without using the foot.
Mallet in a scoop of starting fire, then the other. Afterwards, when a
number are charged, bore through the centre of the plaster, with a
shell-bit, 1/3 the diameter of the case; insert a piece of match in the
hole; wash the face of the plaster over with meal paste, and plunge into
dry meal. A sheet of double-crown makes 8 wheel case envelopes (2.2.2)
10 by 7-1/2, so that the void at each end, to receive the match, is
nearly 1 inch.
It is not possible to devise a formula that will indicate the exact
quantity required for wheel cases, as the fuses vary; but, representing
the length, in inches, by I; and the diameter in eighths by e, the
following will help to serve as a guide.
(I e²)/7 = drams.
Suppose a wheel case 5-5/8 inches long, and 4 eighths diameter,
(5⅝ × 4 × 4)/7 = 90/7 = 13 drams.
Suppose a fixed case 7-1/4 inches long, and 5 eighths diameter,
(7¼ × 5 × 5)/7 = 181/7 = 26 drms. = 1 oz. 10 drms.
_GERBES._
Gerbes, so called from the French word for wheat-sheaf, which they
resemble, are fixed choked cases: they do not show well on wheels. As
they contain grains of iron, they must not be under 6/8; for private
exhibitions a good size is 9/8, 9/8 internal diameter; 12/8 external;
3/8 the diameter of the choke; 11-1/4 inches, length of case. Charge the
case on a nipple, exactly like a wheel case. It is advisable to put in,
first, a little clay, to protect the choke, as the fire, being fierce,
would, otherwise, enlarge it, and diminish the ascent of the sparks.
Upon the clay drive in a scoop of starting fire, and fill up with gerbe
composition. This, when containing iron borings, is termed Chinese fire;
the pieces, Chinese trees.
The most magnificent of all, however, is the coloured gerbe. For this,
some green, blue, and crimson grains, or small stars must be prepared.
They may be quarter-inch cubes, cut as directed for the chopped nitre
stars. A far better way, however, of preparing them, is to remove the
pin a, of fig. 2, up to c, so that the stars, driven in the tube, will
be 5/8 inch diameter, and 3/8 thick. When these are dry, chop them into
4 pieces, by holding a knife, or chisel, across them, and giving it a
smart blow with the mallet. They are harder made this way.
To charge the cases: having driven in the clay, and the starting fire,
put in 7 or 8 stars, then a scoopful of fuse No. 1 or 2, then 7 or 8
more stars, and another scoop of fuse; mallet the whole 4 layers down
firm, with blows not too heavy at a time, but many times repeated. Then
put in 7 or 8 more stars, another scoopful, 7 or 8 more stars, and
another scoop, and mallet the 4 layers as before; and so repeat. The two
layers and the two scoopfuls may fill up, when malleted in, 3/4 of an
inch, in a 9/8 case.
Instead of choking the cases, plaster of paris is far preferable. Let
it be 3/8 of an inch thick, and well dried, before charging. After the
cases are charged, bore a hole through the plaster, 1/3 of a diameter,
that is, with a 9/8 case, 3/8 of an inch diameter. For this purpose it
is not necessary to have another shell-bit; bore it with the 3/16, and
enlarge it with a penknife. It is better arched under, till conical, as
shown in fig. 48. Prime with 4 or 5 pieces of match, and wash with the
sash-tool.
The gerbe being finished, make a cylindrical box, or paper bag, of 2 or
3 thicknesses of paper: fill it with a number of crackers, and a
scoopful of meal powder, and fasten it to the gerbe.
No single piece is more effective than a coloured gerbe; the stars will
be projected 30 feet, or more: they may be put in, mixed; or, one layer
may be blue, another green, another crimson. Twist a piece of wire,
deprived of its elasticity, round the neck, and another piece round the
bottom, and leave long ends; it can then be fastened by them to the top
of a post. To remove the elasticity from iron wire, lay it in the fire
till red hot; withdraw it with the tongs, and put it aside, to cool
slowly. If copper wire is used, it will bend without preparation. String
must not be employed, as it might burn, and let the case fall. Common
pins, patent short whites, deprived of their elasticity, are useful for
connecting the parts of lustres together.
_FLOWER POTS._
These are choked cases, charged with spur fire: the fire is somewhat
slow, so the cases must be short: 4 inches long, and 5/8 diameter is a
good size. Rub the composition thoroughly up in the mortar; the
vegetable black produces beautiful star-like sparks, totally dissimilar
to any other. Put a little composition, at a time, into the case, and
jolt it with the roman candle rammer.
Vegetable black, introduced into a star, causes it to tail, like linseed
oil. Light such star on the hob; it will burn, and leave a residue,
unaltered in shape; blow upon this continuously with the mouth, or,
better still, with a pair of bellows: the supply of oxygen will cause
it to boil up, in a state of fusion, when it will begin to throw out
clusters of the peculiar starlike sparks, before mentioned, bright and
yellow as new sovereigns.
Vegetable black is a pure lamp black; some samples of lamp black make
equally good stars, but others are worthless. Greater reliance can be
placed upon vegetable black. Vegetable black and lamp black must not be
mixed with linseed oil, as such mixture is liable to spontaneous
combustion.
Roll up a tube for pill boxes, of two thicknesses of brown paper. When
dry, cut it into pieces about 1-1/8 inch long: choke one end, like a
wheel case; set it on a nipple,and charge it with spur fire, till full
within 1/16 of an inch: fill up flush with a little plaster of paris,
pressed in flat with a knife: prime the choked end, and put a number of
such cases into a rocket head, or shell.
_PORT FIRES AND SHELL FUSES._
These are unchoked cases, like roman candles; 6 inches long, 3/8
internal, (4-1/2)/8 external, is a good size. They should be rammed, as
hard as possible; and, for this purpose, it is best to have a mould.
Now, if a case is rolled of such a size that it will exactly fit into a
brass tube, and is charged, in it, very hard, it will swell, and it will
be almost impossible to get it out again; but if it be made a trifle
smaller, so as to just slip through the tube; then, if a piece of
writing paper be rolled, dry, round it, once or twice, so as to make it
a tight fit, and the case is charged, it can be pushed out, like a
pellet from a popgun, leaving the writing paper, generally, in the tube,
or mould, and the case will come out without a wrinkle.
Let the composition be put in, very little at a time, and well driven
with a solid rammer and mallet. Fig. 59 represents the mould; the foot b
fits the tube a; the tenon c fits the case; a wire, d, goes through 2
holes in the brass tube, and a hole through the foot; a nut, e, to keep
the wire from jarring out, is made of a piece of indiarubber: make a
hole through it, with a bradawl, and slip it on the wire; or, a
screw-eye may be passed through and held with a leaden, or wooden nut.
_TOURBILLIONS._[A]
A tourbillion, so called from the French word for whirlwind, is a case
made to rotate and ascend at the same time, forming a spiral of fire,
and ending in the shape of an umbrella.
TO MAKE A TOURBILLION.
Roll the case like a roman candle case, but gauge it to the thickness of
a rocket case. Let the inner diameter be 6/8; the outer 9/8; the length
of the case 7-1/4 inches, fig. 43. To charge the case, have a mould, as
directed for port-fires; and let the tenon rise exactly 3/8 of an inch
up the case. Put in a little composition at a time, and mallet it as
firmly as possible, till within exactly 3/8 of an inch of the top of the
case; so that there will be a vacancy of 3/8 of an inch, at each end.
Fill each of these ends flush with plaster of paris. It is, better,
too, if you can manage to fill the middle half-inch of the case with
plaster of paris. It can be effected with care, and will hold the screw,
hereafter to be described, more firmly.
Construct a wooden box, fig. 44, consisting of a bottom and two sides
only, firmly screwed together. Each of the pieces of wood is to be 7-1/4
inches long, and 1/2 an inch thick. The internal breadth of the box is
to be exactly 9/8 of an inch; and its internal depth exactly (4-1/2)/8
or 9/16, so that when the tourbillion is laid evenly in it, and pressed
down to the bottom, half of the case will be in it, and half out of it.
At a point b, fig. 44, on the top of the side, half an inch from a, make
an ink mark: and, at a point d, half an inch from c, make another ink
mark. Fig. 45 is the bottom of the box. At a point w, 5/8 of an inch
from the end; and, at a point z, 5/8 of an inch from the other end, make
holes with a fine bradawl, truly, in a line down the middle of the wood,
as between side and side. The distance w z is 6 inches; divide it into 3
equal parts, in the points x and y, two inches asunder. Bisect x y in
the point s. Procure 5 carpet pins, fig. 47: they will, probably, be
3/4 of an inch long. Drive them through the holes w, x, s, y, z,
inverting the box for the purpose, so that they shall stand bolt upright
in the box. Now screw, or nail a piece of wood over the bottom of the
box, entirely to cover it, to prevent the carpet pins from getting
displaced. It will be seen, that, if the tourbillion be now laid evenly
in the box, and pressed down till it rests on the bottom, the projecting
pins will make 5 holes, in the under part of the case. While it is thus
lying, with a stiletto, such as used by sempstresses, for making eyelet
holes, prick the side of the case over the line b, of fig. 44; and,
also, over the point d. There will now be 7 holes; 5 underneath, 1 to
the right, and 1 to the left: the latter are the places for the
whirlers, or holes of rotation: 4 underneath, for the lifters, or holes
of ascension; the centre one, s, receives a nail or screw. Take a
bradawl, fig. 49, 3/16 of an inch diameter; and slip over it a shield,
consisting of a piece of wood with a central hole up it, like a pop-gun,
of such a length, that, when it is slipped on, only 1/4 of an inch of
the bradawl protrudes; or, instead of a bradawl, fix in a handle, a
wire of equal length, namely 1/4 of an inch, and file it to a point.
Push this into all the holes, except s, making 4 holes underneath, and 2
horizontal holes, one left, one right: all these holes will be exactly
of the same depth, on account of the shield: see that they are bored
perfectly true, the horizontals exactly 90 degrees above the others, or
1/4 of the circumference.
The next thing required, is a piece of hooping, or curved stick, about
6/8 of an inch broad, and as long as the case, 7-1/4 inches. In the
centre of this, bore a hole, and countersink it; then, with a screw, an
inch and a quarter long, screw the hooping, at right angles, on the
bottom of the case, through the point s of fig. 45, which must be
enlarged to receive the screw. A touch of glue may still farther hold
the wood in position. It will now assume the shape of a cross, like
figs. 50 and 51. Fig. 50 shows the under side of the case; fig. 51 the
upper. From w to x lead a bit of naked match; push the ends into both
holes, and secure with a little wetted meal, pressed in with a knife. Do
the same with y and z. Paste a piece of double-crown, 3/4 of an inch
broad, and of sufficient length, and cover each of the two pieces of
match, with two layers of the paper. Turn it over, like to fig. 51;
connect the holes a and b with a bit of naked match; and, under the
centre of it, slip another piece of naked match, having a piece of
touch-paper round the protruding end: cover the match with two
thicknesses of pasted paper, in the same manner as the under holes. The
tourbillion is now complete. See that it will balance, and swing round
easily, when laid upon a level surface. The proper way to fire it, is
from a flat sheet of iron, or a flagstone. Light the touch paper; the
fire will communicate to the side holes, and set it in rotation. As soon
as 1/8 of an inch of fuse has burnt from each end, and the piece has got
well into action, the 4 under holes will catch, and cause it to ascend.
Instead of this mode of making a tourbillion, some charge it with an
inch of solidly rammed clay, in the middle; fasten the stick, by
crossing it with binding-wire; bore a hole through the middle of it, and
of the clay, and slip it over a tapering-wire, standing upright in a
block, like the spindle of a rocket. Four holes only are then used; two
of rotation, and two of ascension; and the whole are fired at once, the
match starting from one of the under holes, going to the side hole;
over, across, to the other side hole, and on to the other under hole.
Instead of making them with clay in the middle, there is yet a better
method of having two cases, each about 4 inches long; and gluing, or
fastening them with tin-tacks on a centre-piece, turned with a tenon at
each end, fig. 52; two balancing arms, one on each side, must then be
fixed to the centre-piece.
In a windmill, as is well known, the vanes, or sails, are set at an
angle. There is a toy, made of two slips of tin, forming a cross, and
set at an angle, sloping upwards, called the flying dutchman; this, when
spun with a string, from a handle like a humming-top, flies up into the
air, on escaping from the string. Steel Fliers, with two vanes, are used
by sportsmen to practise shooting flying. Small balloons, some years
ago, in a room in the Polytechnic Institution, free from a current of
air, were guided or driven by a similar contrivance, moved by
clockwork. The screw-propeller of a ship acts on the same principle. I
think it possible that, if two vanes were fixed in the central piece of
wood, set at an upward angle of 10, 15, or 20 degrees from the
horizontal, they might assist the ascension, and so cause the
tourbillion to reach a greater height; or, the vanes alone might cause
it to rise, upon 4 side holes, two to the left, and two to the right,
causing it to rotate. The design is shown at fig. 54, the shape of the
vane at fig. 53. I have not yet tried it, so offer it only as a
suggestion.
FOOTNOTES:
[A] Tourbillion, from _tourbillon_, like postillion, from _postillon_,
the i being inserted to approximate the pronunciation of the French. In
pavilion, from _pavillon_, and vermilion, from _vermillon_, one l is
dropped; so in battalion, from _bataillon_; while medallion, from
_medaillon_, retains the ll.
_SAXONS._