black mass and draws out all the colors of the rainbow. This
evil-smelling substance beats the rose in the production of perfume and
surpasses the honey-comb in sweetness.

Bishop Berkeley, after having proved that all matter was in your mind,
wrote a book to prove that wood tar would cure all diseases. Nobody
reads it now. The name is enough to frighten them off: "Siris: A Chain
of Philosophical Reflections and Inquiries Concerning the Virtues of Tar
Water." He had a sort of mystical idea that tar contained the
quintessence of the forest, the purified spirit of the trees, which
could somehow revive the spirit of man. People said he was crazy on the
subject, and doubtless he was, but the interesting thing about it is
that not even his active and ingenious imagination could begin to
suggest all of the strange things that can be got out of tar, whether
wood or coal.

The reason why tar supplies all sorts of useful material is because it
is indeed the quintessence of the forest, of the forests of untold
millenniums if it is coal tar. If you are acquainted with a village
tinker, one of those all-round mechanics who still survive in this age
of specialization and can mend anything from a baby-carriage to an
automobile, you will know that he has on the floor of his back shop a
heap of broken machinery from which he can get almost anything he wants,
a copper wire, a zinc plate, a brass screw or a steel rod. Now coal tar
is the scrap-heap of the vegetable kingdom. It contains a little of
almost everything that makes up trees. But you must not imagine that all
that comes out of coal tar is contained in it. There are only about a
dozen primary products extracted from coal tar, but from these the
chemist is able to build up hundreds of thousands of new substances.
This is true creative chemistry, for most of these compounds are not to