57. I have next a formula to offer which I think has considerable merits
of its own. It produces a purple colour of a very pleasing tint, and has
also very considerable illuminating power. I have never seen a colour of
this kind employed in any pyrotechnic exhibition, but I believe it to be
an effective composition, and one certainly that will make a change from
the ordinary routine of white, green, and red. I shall dignify it by the
title of—
PURPLE FIRE.
No. 9.
Nitre 48 parts.
Sulphide of copper 12 „
Sulphur 12 „
Calomel 6 „
Arsenic 6 „
Nitrate of strontia 6 „
Chlorate of potash 4 „
Shellac 4 „
Charcoal (fine) 1 part.
I trust that my readers will not be alarmed at the number of ingredients
in the above formula. I can only promise them that the colour produced
is an extraordinary one, and cannot be produced by ordinary means. You
will observe that I have recommended 12 parts of sulphide of copper.
This must be the _fused_ sulphide. Or you may substitute for it equal
parts of Chertier’s copper and sulphide of copper, or equal parts of
Chertier’s, or of sulphide of copper and fine black oxide of copper. The
_arsenic_ employed in the formula may be either orpiment or realgar, but
by far the best preparation of arsenic for this purpose is the _finely
powdered metallic arsenic_. Formula No. 9 is one of my own introduction.
It possesses the advantages of being perfectly safe, deep-tinted, and
decidedly illuminative. But I do not pretend to say that it can ever be
admired to the same extent with the red and the green fires. These
latter will always take the precedence, for their effect at night is so
thoroughly theatrical and surprising that no other colour, however
beautiful or extraordinary, can hope to supersede them. I was once asked
by a lady to make a _brown-coloured_ flame. The idea was so rich in
theory that I never attempted to dissolve its charm by any failures in
experimental practice. But had I succeeded to the utmost with this brown
fire, no illuminating properties could ever have been obtained. One
might as well have expected a good effect from a _black star_ or a
_neutral tinted sun_.