rom, or even make it. The old alchemist was
a secretive and pretentious person and used to invent queer names for
the purpose of mystifying and awing the ignorant. But the chemist in
dropping the al- has dropped the idea of secrecy and his names, though
equally appalling to the layman, are designed to reveal and not to
conceal.

From this brief explanation the reader who has not studied chemistry
will, I think, be able to get some idea of how these very intricate
compounds are built up step by step. A completed house is hard to
understand, but when we see the mason laying one brick on top of another
it does not seem so difficult, although if we tried to do it we should
not find it so easy as we think. Anyhow, let me give you a hint. If you
want to make a good impression on a chemist don't tell him that he
seems to you a sort of magician, master of a black art, and all that
nonsense. The chemist has been trying for three hundred years to live
down the reputation of being inspired of the devil and it makes him mad
to have his past thrown up at him in this fashion. If his tactless
admirers would stop saying "it is all a mystery and a miracle to me,
and I cannot understand it" and pay attention to what he is telling them
they would understand it and would find that it is no more of a mystery
or a miracle than anything else. You can make an electrician mad in the
same way by interrupting his explanation of a dynamo by asking: "But you
cannot tell me what electricity really is." The electrician does not
care a rap what electricity "really is"--if there really is any meaning
to that phrase. All he wants to know is what he can do with it.

[Illustration: COMPARISON OF COAL AND ITS DISTILLATION PRODUCTS From
Hesse's "The Industry of the Coal Tar Dyes," _Journal of Industrial and
Engineering Chemistry_, December, 1914]

The tar obtained from the gas plant or the coke plant has now to be
redistilled, giving off the ten "crudes" already mentioned and leaving
in the still sixty-five per cent. of pitch, which may be used for
roofing, paving and the like. The ten primary products or crudes are
then converted into secondary products or "intermediates" by processes
like that for the conversion of benzene into aniline. There are some
three hundred of these intermediates in use and from them are built up
more than three times as many dyes. The year before the war the American
custom house listed 5674 distinct brands of synthetic dyes im