building containing them when water for extinguishment was put on. Any
one who has seen the brilliance with which potassium and sodium burn
upon water can easily imagine how such strong affinity of oxygen for
these substances might aid in severing its union in water in their
presence and under extraordinary heat. It might be safe so say that the
presence of water under very high temperature may be as aidful to form
an explosive among such salts as have been named, as sulphur is for the
rapid combustion of gunpowder.

In the review for August, 1862 (Saltpeter Deflagrations in Burning
Buildings and Vessels--Water as an Explosive Agency), it was shown that
Mr. Boyden's experiments in 1861-62 proved that explosions would occur
when water was put upon niter heated alone, and stronger explosion from
niter, drywood, and sulphur; also explosion when melted niter was poured
on water. The following points we reproduce for comparison: If common
salt be heated separately to a bright heat, and water _at_ 150 deg. F.
poured on it, an explosion will occur. Niter mixed with common salt,
placed upon burning charcoal, and water added, produce a stronger
explosion than salt alone. Heating caustic potash to a white heat, and
adding _warm or hot water_, produces explosion. At a Boston fire small
explosions were observed upon water touching culinary salt highly
heated. Anthracite coal and niter heated in a crucible exploded when
_sea water_ was poured on them.

The production of explosion by the putting of water on nitrate of
potassium and chloride of sodium arises from the union, at high
temperature, of the oxygen of the water with the potash and soda. Of the
three liberated gases, hydrogen only is inflammable, and the other two
suffocative of flame; but together the nitrogen and chlorine are not to
be undervalued, for chloride of nitrogen is ranked as the most terrible