33. I must now suppose your stars and cases to be ready for use; and,
therefore, the next thing to be considered will be the composition which
is to form the intervals between the stars in the cases. For this
purpose I give you three formulas.
COMPOSITION FOR ROMAN
CANDLES.
No. 1.
Nitre 18 parts.
Sulphur 6 „
Charcoal (fine) 7 „
Meal-powder 4 „
This composition is one which answers very well. I think, however, that
the following is better, being rather more rapid in its combustion, and
thus capable of producing a more decided effect when burning at the
lower end of the case:—
No. 2.
Nitre 16 parts.
Meal-powder 8 „
Charcoal (fine) 6 „
Sulphur 6 „
This is the composition which I generally employ. Both of these formulas
give rather a dusty mixture, and can be used with much greater
cleanliness and comfort if slightly moistened. Only so much spirits of
wine or gin must be used as will render them less dusty, and not wet.
The following composition is very useful, but produces rather a jet of
flame with sparks than a rich sparkling fountain:—
No. 3.
Nitre 16 parts.
Meal-powder 11 „
Sulphur 6 „
Antimony 4 „
This composition is of a more heavy and less dusty nature, but can also
be slightly moistened, if you find it more convenient to use it when
thus treated. Take care that in each case the ingredients are well
mixed.
ROMAN-CANDLE CASES (To Fill).
34. Having selected one of the above compositions, you will now be ready
to fill your cases. For this part of your work you will require a small
turned block of wood, like that drawn in the page of illustrations (fig.
40). This block with its projecting piece is called a “settle.” One end
of your Roman-candle case is pressed over the upper part of this settle,
which is made of a size to fit into it tightly. By this means the case
will be supported while it is being filled. The first thing to be done
is to close up one end of the case. This is done by ramming in a small
quantity of dry potter’s clay, such as you used for rockets; this being
driven down over the top of the settle will form a very hard, firm end.