467 
ON IMPROVED SHAPE FOR MOULDING GUNPOWDER, 
BY 
LIEUT.-COL. M. TWEEDIE, R. A. 
Of the various gunpowders manufactured for the use of modern 
heavy ordnance, that called the German prismatic has undoubtedly 
given the best results. 
These good results have been attained mainly from its peculiar shape; 
an hexagonal prism with a hole through the centre, and to the nature 
of the surface given to the faces of the prisms. 
The cartridge is built up of these hexagonal prisms, the holes through 
which will coincide, and form a passage for the flame to pass rapidly 
through, igniting the surface of the holes. Each prism of gunpowder 
will then burn from the interior to the exterior, on a constantly in¬ 
creasing surface, and thus making it, what is termed, a progressive 
gunpowder. The faces of the prisms are given a surface that will not 
rapidly ignite, and this, in conjunction with the size of the holes, 
limits the amount of gunpowder at first ignited, regulating the 
pressure. 
In theory, and also in practical results, this gunpowder is excellent, 
but it is open to the following objections :— 
It is expensive, and neither easily nor safely manufactured. It can 
only be moulded in short prisms on account of having to make the hole 
through the centre. It has all to be bought from foreign manufacturers, 
as it has not yet been successfully made in this country. 
It must be admitted by all, that the manufacture of gunpowder is 
now in a very crude state, as compared with what we may expect to see 
within the next few years. I presume that the fear of accident has 
contributed to its manufacture having been simply handed down 
traditionally, without deviation from established custom; however, I am 
not at present going to enter into this subject of gunpowder further 
than to suggest a different shape for prismatic gunpowder, with the 
view of overcoming, so far as possible, the objections to the German 
prismatic gunpowder above named. 
