and carefully studied theories as to the composition of the
atmosphere. This was an important step, and although Boyle is not
directly responsible for the phlogiston theory, it is probable
that his experiments on the atmosphere influenced considerably
the real founders, Becker and Stahl.

Boyle gave very definitely his idea of how he thought air might
be composed. "I conjecture that the atmospherical air consists of
three different kinds of corpuscles," he says; "the first, those
numberless particles which, in the form of vapors or dry
exhalations, ascend from the earth, water, minerals, vegetables,
animals, etc.; in a word, whatever substances are elevated by the
celestial or subterraneal heat, and thence diffused into the
atmosphere. The second may be yet more subtle, and consist of
those exceedingly minute atoms, the magnetical effluvia of the
earth, with other innumerable particles sent out from the bodies
of the celestial luminaries, and causing, by their influence, the
idea of light in us. The third sort is its characteristic and
essential property, I mean permanently elastic parts. Various
hypotheses may be framed relating to the structure of these later
particles of the air. They might be resembled to the springs of
watches, coiled up and endeavoring to restore themselves; to
wool, which, being compressed, has an elastic force; to slender
wires of different substances, consistencies, lengths, and
thickness; in greater curls or less, near to, or remote from each
other, etc., yet all continuing springy, expansible, and
compressible. Lastly, they may also be compared to the thin
shavings of different kinds of wood, various in their lengths,
breadth, and thickness. And this, perhaps, will seem the most
eligible hypothesis, because it, in some measure, illustrates the