The third kind of high explosives uses as its base toluol. This is not
so familiar to us as glycerin, cotton or carbolic acid. It is one of the
coal tar products, an inflammable liquid, resembling benzene. When
treated with nitric acid in the usual way it takes up like the others
three nitro groups and so becomes tri-nitro-toluol. Realizing that
people could not be expected to use such a mouthful of a word, the
chemists have suggested various pretty nicknames, trotyl, tritol,
trinol, tolite and trilit, but the public, with the wilfulness it always
shows in the matter of names, persists in calling it TNT, as though it
were an author like G.B.S., or G.K.C, or F.P.A. TNT is the latest of
these high explosives and in some ways the best of them. Picric acid has
the bad habit of attacking the metals with which it rests in contact
forming sensitive picrates that are easily set off, but TNT is inert
toward metals and keeps well. TNT melts far below the boiling point of
water so can be readily liquefied and poured into shells. It is
insensitive to ordinary shocks. A rifle bullet can be fired through a
case of it without setting it off, and if lighted with a match it burns
quietly. The amazing thing about these modern explosives, the organic
nitrates, is the way they will stand banging about and burning, yet the
terrific violence with which they blow up when shaken by an explosive
wave of a particular velocity like that of a fulminating cap. Like
picric acid, TNT stains the skin yellow and causes soreness and
sometimes serious cases of poisoning among the employees, mostly girls,
in the munition factories. On the other hand, the girls working with
cordite get to using it as chewing gum; a harmful habit, not because of
any danger of being blown up by it, but because nitroglycerin is a heart
stimulant and they do not need that.

[Illustration: The Genealogical Tree of Nitric Acid From W.Q. Whitman's