£84 
MINUTES OF PEOCEEDINGS OF 
other of their ingredients, or from so apparently trifling a cause as the 
absorption of a small amount of moisture, or the employment of a small 
quantity of an easily oxidisable oil or fat in connection with their 
application to pyrotechnic purposes. Two remarkable instances of 
unforeseen danger in dealing with materials of this kind, even when their 
stability, under normal conditions, is beyond question, have come under 
the notice of the speaker. In one case, an explosive mixture, prepared 
for use in percussion caps, was preserved in a moist condition with the 
view of storing it in a non-explosive form, but this very precaution gave 
rise to a serious explosion; chemical activity became established between 
the components of the mixture, through the agency of the water, 
attended by development of heat and the speedy production of violent 
chemical change—a result which would certainly not have occurred had 
the mixture been kept dry. In the other instance, some signal lights, 
composed of a mixture of ingredients which long experience had shown to 
be in every way as permanent as those of gunpowder, were found to 
be undergoing decomposition to an extent which, had it not been 
noticed in time, must have resulted in serious consequences. The 
cause of this change baffled enquiry for some time, but ultimately it 
was clearly established that a very minute quantity of free acid contained 
in the paper linings of the cases in which the composition was confined 
(and derived from the antichlore used in the manufacture of the paper) 
had set up an action between the saltpetre and the orpiment composing 
this material, which spread gradually but with increasing rapidity 
through the highly compressed mass, being of course accelerated by the 
heat developed. Such occurrences afford instructive illustrations of the 
dangers which surround the manufacture and application of explosive 
substances, and of the necessity for combining continued study with 
untiring vigilance in dealing with these branches of manufacture. 
Many of the most distressing accidents connected with firework 
manufacture have occurred in dwelling houses of the lower class, situ¬ 
ated in crowded districts, in which not unfrequently several families 
reside, and where people, generally in very poor circumstances, have 
carried on the manufacture of squibs, crackers, or pin-wheels, which 
they have either retailed, or generally supplied to more extensive 
firework makers or sellers. This production of fireworks has almost 
always been carried on illegally— i.e., without the maker having obtained 
the licence necessary, under an existing Act of Parliament, to enable him 
to manufacture fireworks; hence work of this kind has mostly been 
conducted as secretly as possible, other dwellers in the same house being 
often unaware of the dangerous operations carried on in the house itself, 
or sometimes in small sheds or outhouses. It can only be matter of 
surprise that firework accidents have not been more numerous, when it 
is remembered that the processes of mixing the firework compositions, 
ramming them into cases, &c., have frequently been carried on by these 
illegal makers in the common dwelling room, the several members of the 
family, old and young, taking part in the work, while cooking and even 
smoking may have been going on in the same room, and the work con¬ 
tinued by candlelight in busy seasons, the powder or finished fireworks 
being placed in a cupboard in the room, or perhaps in places afford- 
