30 
MR. gale’s non-explosive GUNPOWDER. 
and even then this was not entirely accomplished. Nothing, therefore, could possibly 
have been more complete than the success of the experiment, though the value of the 
invention will perhaps be more fully appreciated if we explain in a few words how 
simply such an astounding result is brought about. 
It is nearly fifteen years since Mr. Gale began to direct his attention as a chemist and 
electrician to the discovery of a material which when mixed with gunpowder should 
render the whole mass at once fireproof, waterproof, and airtight, and at the same time 
he easily separable, and when separated leave the gunpowder totally uninjured. It is 
needless to say how many and how combined were the compositions tried before one at 
last was found to fulfil all these apparently irreconcilable conditions. This composition 
is nothing more nor less than powdered glass prepared in a peculiar manner. The com¬ 
monest glass is heated to a bright whiteness and then plunged into cold water, which 
utterly destroys all the little fibre and elasticity glass can ever be said to possess, and 
renders it so friable as to be easily pressed to powder between the fingers. In this state 
it is placed in a machine shaped like a cask, in which are many small iron shot, and the 
machine being revolved rapidly, a minute or a minute and a half suffices to reduce the 
glass to a powder so impalpable that even fine wheat flour is coarse in comparison with 
it. This is mixed with the powder in the proportion of two parts to one, if it is only 
meant to render it non-explosive, but still leave it fiercely combustible ; in the propor¬ 
tion of three parts of ground glass to one of common powder, if it is meant to make it 
almost incombustible ; and in the proportion of four parts to one of the strongest gun¬ 
powder to make the latter absolutely harmless. Four parts are, however, generally con¬ 
sidered necessary only for the strongest Government common powder. The method of 
mixing the two is simply by an adaptation of Kobinson’s cask-cleaning machine, which 
gives to the cask it holds a rapid double motion, two minutes of which is sufficient to 
blend the ground glass and the coarse grains of powder perfectly. So complete is this 
mixture that of forty samples taken from as many casks after two minutes’ mixing, the 
relative proportions of the two materials were found to be in all cases absolutely exact. 
The forty 5 lb. samples when separated were all found to contain precisely 1 lb. of gun¬ 
powder and 4 lb. of powdered glass. The separation of the powder from the glass is 
made in a few seconds by coarse copper sieves. The grain of the best Government 
powder for cannon is nearly as large as a coffee bean, and this coarseness, combined with 
the fineness and weight of the powdered glass, enables the two to be separated almost in¬ 
stantaneously, and a very simple piece of copper machinery has been devised which 
will effect this process even more quickly and on the largest scale. One of the most im¬ 
portant questions to be ascertained was whether the minute portions of the po'wdered 
glass, which more or less adhered to the grains of gunpowder after sifting, in any way 
affected its explosive qualities. For some time past, therefore, the Ordnance Select Com¬ 
mittee have made a most careful series of experiments to resolve this doubt, and the 
decision they have come to is, that neither in rapidity of ignition nor explosive force is 
the gunpowder in any way deteriorated. Not only is it not injured, but its complete 
preservation from damp—almost as important in the case of powder as its preservation 
from fire—makes Mr. Gale’s method of mixing far preferable to the present mode of 
stowage. The objections to the bulk which powder when thus mixed would occupy in 
the Government stores have also in a great measure disappeared upon examination. 
About twenty-five per cent, of the kegs in which gunpowder is now packed are left 
empty that the grains may be free to roll, and so prevent their “ cakeing.” This neces¬ 
sary precaution, however, induces another evil, which is that the constant friction of the 
grains often reduces half the contents of a keg to dust, and immense quantities are thus 
yearly returned to the mills to be recorned before it can be used. Of course, against all 
these evils of fire, water, friction, or deterioration, Mr. Gale’s discovery is an absolute 
specific. With the adoption of his plan all the necessities for costly magazines would 
disappear, and so also would those huge spaces of waste land which are obliged to be 
kept free round these perilous storehouses, and on which farmers may not venture to 
cultivate nor architects to build. In the matter of transport alone this new method of 
mixing powder would effect a saving of £5. 10s. per ton. 
As we have said, the Ordnance Select Committee have tried the mixture in almost 
every possible way, and always with the same unvarying success. Barrels of gunpowder 
thus protected have been placed on bare fires, have had red-hot pokers thrust into them, 
and the loose mixture has been thrown by shovelfuls into fires, but all in vain. It 
