to build so
very important a branch of chemistry. This science of affinities, or
elective attractions, holds the same place with regard to the other
branches of chemistry, as the higher or transcendental geometry does
with respect to the simpler and elementary part; and I thought it
improper to involve those simple and plain elements, which I flatter
myself the greatest part of my readers will easily understand, in the
obscurities and difficulties which still attend that other very useful
and necessary branch of chemical science.

Perhaps a sentiment of self-love may, without my perceiving it, have
given additional force to these reflections. Mr de Morveau is at
present engaged in publishing the article _Affinity_ in the Methodical
Encyclopaedia; and I had more reasons than one to decline entering upon a
work in which he is employed.

It will, no doubt, be a matter of surprise, that in a treatise upon the
elements of chemistry, there should be no chapter on the constituent and
elementary parts of matter; but I shall take occasion, in this place, to
remark, that the fondness for reducing all the bodies in nature to three
or four elements, proceeds from a prejudice which has descended to us
from the Greek Philosophers. The notion of four elements, which, by the
variety of their proportions, compose all the known substances in
nature, is a mere hypothesis, assumed long before the first principles
of experimental philosophy or of chemistry had any existence. In those
days, without possessing facts, they framed systems; while we, who have
collected facts, seem determined to reject them, when they do not agree
with our prejudices. The authority of these fathers of human philosophy
still carry great weight, and there is reason to fear that it will even
bear hard upon generations yet to come.

It is very remarkable, that, notwithstanding of the number of
philosophical chemists who have supported the doctrine of the four
elements, there is not one who has not been led by the evidence of facts
to admit a greater number of elements into their theory. The first
chemists that wrote after the revival of letters, considered sulphur and
salt as elementary substances entering into the composition of a great
number of substances; hence, instead of four, they admitted the
existence of six elements. Beccher assumes the existence of three kinds
of earth, from the combination of which, in different proportions, he
supposed all the variet