6. Now we come to the actual ramming of the rockets; and, unless you
intend to be a great nuisance to your friends and neighbours, you had
better not dream of performing this operation indoors, it being
productive of much noise and jarring; and you will find that they will
not take much interest in your pyrotechnic progress when they have been
annoyed and deafened by your frantic efforts for their amusement. You
had better choose, therefore, some place either out-of-doors, or in an
outhouse, where you are not likely to be interrupted or interfered with;
the outhouse, of course, will be preferable, because there you will not
be exposed to wind and weather, the former of which, especially, is
often a source of considerable inconvenience when working out-of-doors.
But whatever place you decide upon, you must have a very solid block of
some kind, which is better made either of wood or stone, and must be set
upon, or let into, solid ground. I should think that you will find no
difficulty in meeting with one, made of either of these materials, in
any carpenter’s or builder’s yard; odd pieces of stone and timber which
would answer your purpose may generally be procured for a few pence. The
stone block which I use is about 12 + 8 + 8 inches. On your block I
recommend you to put nothing but the wooden block into which your
spindle is fixed. The composition which you are using should never be
placed upon it, because it is sure to become to some extent unmixed by
the concussion caused by the blows of your mallet, for the particles of
any coarse ingredient which it contains will find their way to the
surface. You will find it advisable to have your block, and the table on
which your tools and composition are placed, of such a height from the
ground that, in working, you need not stoop or put yourself into any
uncomfortable attitude.
Next we have to consider what is the most convenient receptacle for your
composition while your cases are being filled with it. I use a copper
scoop capable of holding about 8 ounces of composition, made something
like an open coal-scuttle in form, which I have always found very
convenient, and which is represented in the annexed woodcut (fig. 17).
[Illustration:
Fig. 17.
]
You will next require a small ladle made of thin copper or brass, of
such a size that it will take up just as much composition as you should
put into your case at a time, and will admit of being passed into the
case. By means of this you will be able to drive in the composition very
uniformly, for by giving a certain number of blows of a certain power to
each ladleful, you can be sure of an equal compression throughout the
length of the case. Such a ladle Mr. Newman will supply with your rocket
tools, of the right size for filling ¼ lb. cases.
I will now suppose you to be ready at the ramming-block, with all your
tools about you, your composition ready, and your case driven firmly
down over your spindle. I strongly recommend a slight moistening of the
composition as directed above before you begin to ram it. Now, taking
the longest of the drifts (fig. 13) in your left hand, insert into the
case when the first ladleful of composition has been put in. You are not
to suppose that by “a ladleful” I mean as much composition as can be
heaped up upon the ladle or scoop, but as much as will lie within it
after you have passed the drift over its surface, and have levelled the
composition to the height of its sides. To this first ladleful of
composition give _fourteen_ blows with the mallet: it is not necessary
to exert much force in this operation, for the weight of the mallet will
be nearly enough to do the work for you; and you will find that after
each stroke the mallet will recoil with the blow to a point almost high
enough to be the starting-point for the next stroke. Having given the
proper number of blows, take another ladleful of composition, and when
you have put it into the case, drive it down in the same manner as the
former one with the same number of blows. Then for your third ladleful
take the longest drift but one, which must be used for this and the
following ladleful, giving to each of them _sixteen_ blows. Then take
the shortest hollow drift, and use this for as many ladlefuls as will
make the composition rise to the top of the steel spindle, giving
eighteen blows to each of them. Then by inserting the short, solid
drift, you will be able to measure the distance between the top of the
spindle and the top of the case. When you have taken this measurement,
make a mark, on _the outside_ of the case, which will show you how high
the spindle rises on the inside. By adopting this plan, or any other
that may occur to you as simple, you will always be able to ram the same
quantity of solid composition above the spindle. This is really an
important matter, and one on which depends mainly the beauty of your
rocket’s performance when it reaches its greatest elevation in the air.
There are great varieties of opinion as to what should be the quantity
of composition rammed solid above the spindle, and it is a much more
common matter to find too little than too much composition used for this
purpose. The effect of using too little is, that the rocket does not
fairly arrive at its turn before its stars or other decorations are
thrown out. This, in my opinion, is a considerable fault; for it robs
the rocket of a great deal of the elegance of its flight, and gives one
the idea that it is in a hurry to get its work over. Nothing but actual
experience and observation will enable any one to decide which he
considers the proper quantity of solid composition. I consider the best
length for this part of the rocket to be that of _the exterior diameter
of the case_—that is, an inch or rather more for rockets of the ¼lb.
size. Larger rockets, I have always found, do not require quite so much
in proportion; smaller rockets rather more. You should give twenty blows
with the mallet to each ladleful of this solid composition. I am well
aware that this number of blows sounds like a great deal of hard work,
but you may rest assured that these twenty blows, given as I have
directed above, will occupy only five or six seconds of time, at the
cost of very little exertion.
Having now completed the ramming of the composition into your case, you
will next require some common potter’s clay in dry powder; this can be
procured of Mr. Darby in a condition proper for use. Take
half-a-ladleful of it, and ram it down very hard upon the top of the
composition with the solid drift. This clay when thus compressed will
form an end to your rocket nearly as hard as stone—not so hard, however,
but that you can bore a hole through it about ⁵⁄₁₆ths of an inch in
diameter, which will allow of the necessary connexion between the rammed
composition and the stars or other contents of the head of your rocket.
In the next place I will speak of the