BRITISH PHARMACEUTICAL CONFERENCE, 1865. 
119 
burns rapidly, it is true, but progressively, and its degree of explosiveness depends mainly 
upon the rapidity of that burning. Evidently, then, anything which tends to diminish 
its rapidity of burning tends also to diminish its explosiveness. Now, the rapidity of 
burning is enormously influenced by the facility to the expansion of the gases generated 
by the first ignited grains. The requisite facility is afforded in ordinary gunpowder by 
breaking it into grains, and so creating a number of interstices, dependent for their size 
and extent upon the size and shape of the grains, through which the gas can readily 
wind its way. Now, if these interstices are filled up with a foreign substance, in pro¬ 
portion to the quantity of that substance, and the completeness with which, so to speak, 
the pores of the powder are closed, so must the rapidity of burning of the powder, and 
hence its explosiveness, be diminished. If enough of the substance be added, as in Mi. 
Gale’s mixture, each grain being then actually shut off and separated from its neighboui, 
the powder cannot burn at all, and the result described in your columns follows. Piobert’s 
experiments showed that the powdered substances need not even be non-combustible ; on 
the contrary, sulphur, charcoal, and saltpetre, gave better results than sand ; indeed, 
finely powdered gunpowder introduced between the grains will itself materially retard 
inflammation, and it is well known that “ mealed ” or “ dust ” powder burns less rapidly 
than granulated powder, from this cause ; and, similarly, the_ explosiveness of powder 
which has become “ dusty ” is much diminished. Where, then, is the difference between 
Mr. Gale’s system and that of MM. Piobert and Fadeieff ? The one used powdered glass, 
the others employed various powdered substances more or less suitable. . The English¬ 
man adds rather more of his glass, and so prevents his powder from burning at all; the 
Frenchman added as much as he thought necessary to diminish the rapidity of burning 
to the point which sufficed to deprive the action of the powder of its dangerously explo¬ 
sive character; and, instead of employing 3 to 1 or 4 to 1, like Mr. Gale, used only 
1 to 2. . 
I must not venture to trespass upon your space with lengthy extracts from riobeixs 
work upon this subject. The references which I have given will be sufficient for such 
of your readers as may care to inquire further into this matter. I have no wish to 
detract from Mr. Gale’s merits, but palmam qui meruit ferat. 
Nor do I wish to pronounce an unfavourable opinion as to the practical value of the 
plan; indeed, in the absence of experiments on a much more complete and extended 
scale’than those which have yet taken place with Mr. Gale’s powder, it would be unfair 
to do so ; but it should be noticed that the objection which you refer to on the score of 
increase ’of bulk is by no means the only one which presents itself. For example, the 
shooting quality of the powder will, of course, depend upon the completeness with which 
the sifting process is performed ; and here we have at once a serious element of uncer- 
taintv, the extent of which, in these days of accurate shooting, will be readily appre¬ 
ciated. Then, again, it is a question if the glass will not destroy, in a great measure, 
the glaze and surface of the powder, thus materially altering its character. The mixing 
and sifting processes will always be attended with more or less danger; and it is ques¬ 
tionable to what extent the mixture would remain complete in transport, and in propor¬ 
tion as the powder becomes unmixed, so does it become more explosive, and our fancied 
security, by inducing us to dispense with precautions, might actually lead to the serious 
consequences which Mr. Gale seeks to avert. • 
BRITISH PHARMACEUTICAL CONFERENCE, 1865. 
The members of Conference are reminded that the meeting for the present 
year will be held at Birmingham, at the Odd Fellows’ Hall Temple Street. It 
will commence on Tuesday, the 5th of September, at ten a.m., and be continued 
on Wednesday, the 6tli, at the same hour, and on Thursday and Friday, the 
7th and 8th of September, at seven o’clock in the evening. 
The Birmingham Committee of Management hope to welcome a large number 
of those who "are interested in the promotion of Pharmaceutical scieiice. In 
addition to the attractions of the Conference, the simultaneous occurrence of the 
meetings of the British Association, and the various objects of scientific interest 
