freezes at about 46; it is made to decompose in a very peculiar way; on
moistening paper with it it burns with rapidity; it does not explode
when red-hot copper is placed in it; we tried it with the most intense
heat--we can produce with a galvanic battery with two hundred cells
holding a gallon and a half each; some nitro-glycerin was placed in a
cup and connected with one of the poles of the battery; through a pencil
of gas carbon the other poles of the battery were connected with the
glycerin, no explosion ensued; but when the point touched the britannia
vessel the nitro-glycerin took fire, a portion burning and the rest
scattering about; this is as severe a test as we can submit it to in the
way of heat under the pressure of the air; we therefore would conclude
that nitro-glycerin carried about exposed cannot explode, even if you
drop a coal of fire into it; if the liquid is confined, or is under
pressure, then an explosion will ensue; if paper be moistened with
it and put on an anvil and a smart blow given with a hammer, a sharp
detonation ensues; if gunpowder or the fulminates of mercury, silver or
gun-cotton be ignited in a vacuum by a galvanic battery, none of them
will explode; if any gas be introduced so as to produce a gentle
pressure during the decomposition, then a rapid evolution of gases will
result; the results of decomposition in a vacuum differ from those under
atmospheric pressure or when they are burnt in a pistol, musket,
a cannon, or in a mine; where we have little or no pressure it is
difficult to get these substances to burn rapidly; nitro-glycerin is
more difficult to explode than powder; in many respects it resembles
gun-cotton which is made in a similar way; if gun-cotton be immersed
in the proto-chloride of iron it turns into common cotton; the
same experiment was tried with nitro-glycerin by mixing it with
proto-chloride of iron, and it reverted into common glycerin; there
are four well known varieties of gun-cotton made by employing acids of
different strengths; they differ in chemical composition and properties,