writers of his time. In _The Sceptical Chymist_ (published 1678-9) he
says: "If judicious men, skilled in chymical affairs, shall once agree
to write clearly and plainly of them, and thereby keep men from being
stunned, as it were, or imposed upon by dark and empty words; it is to
be hoped that these [other] men finding, that they can no longer write
impertinently and absurdly, without being laughed at for doing so,
will be reduced either to write nothing, or books that may teach us
something, and not rob men, as formerly, of invaluable time; and so
ceasing to trouble the world with riddles or impertinences, we shall
either by their books receive an advantage, or by their silence escape
an inconvenience."

Most of the alchemists taught that the elements produced what they
called _seed_, by their mutual reactions, and the principles matured
this seed and brought it to perfection. They supposed that each class,
or kind, of things had its own seed, and that to obtain the seed was
to have the power of producing the things which sprung from that seed.

Some of them, however, asserted that all things come from a common
seed, and that the nature of the products of this seed is conditioned
by the circumstances under which it is caused to develop.

Thus Michael Sendivogius writes as follows in _The New Chemical Light,
drawn from the fountain of Nature and of Manual Experience_ (17th
century):--

"Wherever there is seed, Nature will work through it, whether it
be good or bad." "The four Elements, by their continued action,
project a constant supply of seed to the centre of the earth,
where it is digested, and whence it proceeds again in generative