A History of Research and a Review of Recent Developments

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The nature of explosions
1.1 THE DEVELOPMENT OF LOW AND HIGH EXPLOSIVES
Historians of science tell us that the explosives industry began with gunpowder,
made by hand-mixing potassium nitrate (saltpetre), carbon (charcoal) and
sulphur in a chemist’s mortar. Most schoolboys are familiar with this basic
mixture from their chemistry lessons, where they were taught that the ideal
proportions should be based on the atomic weights of the components, about
75:13:12. However, the gunpowder of the thirteenth century, developed by
the English philosopher and scientist Roger Bacon, was rather short on the
saltpetre, and his proportions were about 40:30:30. It is of interest that Bacon
was born near Ilchester in Somerset and that he turned to science and philosophy
when forced to retire from his work as an academic. There is hope here for all
disillusioned academics! Like so many creative inventors his work was marked
by a foresight based on imaginative speculation, in which he combined the
cross-reading of various sciences with a knowledge of the ways of history and
human error.
The shortfall on saltpetre was probably because this compound was not
available in a sufficiently refined form at the time of Bacon, but once it had been
shown that after ignition his mixture would burn with great speed, and give rise
to large quantities of gas, the military soon became interested. Following ignition
in a confined space large pressures could be used to propel missiles such as lead
shot and cannonballs. Black powder, named because of the charcoal content,
was quite dangerous to handle because of the possibility of spontaneous ignition,
but this did not stop the mechanization of the mixing process over the centuries.
Batteries of pestles and mortars were powered by horse or water power, but by
the end of the eighteenth century in England there had been so many fatal
accidents that these ‘stamp-mills’ were forbidden. It was also found that ramming
the powder into the breaches of guns was a very tricky business. If packed too
tightly burning was so slow that there was an insufficiently rapid build-up of
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