ender 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 production
of the elastic particles we are considering. For no art or curious
instruments are required to make these shavings whose curls are in no
wise uniform, but seemingly casual; and what is more remarkable, bodies
that before seemed unelastic, as beams and blocks, will afford them."(1)

Although this explanation of the composition of the air is most crude,
it had the effect of directing attention to the fact that the
atmosphere is not "mere nothingness," but a "something" with a
definite composition, and this served as a good foundation for future
investigations. To be sure, Boyle was neither the first nor the only
chemist who had suspected that the air was a mixture of gases, and not
a simple one, and that only certain of these gases take part in the
process of calcination. Jean Rey, a French physician, and John Mayow, an
Englishman, had preformed experiments which showed conclusively that the
air was not a simple substance; but Boyle's work was better known, and
in its effect probably more important. But with all Boyle's explanations
of the composition of air, he still believed that there was an
inexplicable something, a "vital substance," which he was unable to
fathom, and which later became the basis of Stahl's phlogiston theory.
Commenting on this mysterious substance, Boyle says: "The difficulty
we find in keeping flame and fire alive, though but for a little time,
without air, renders it suspicious that there be dispersed through the
rest of the atmosphere some odd substance, either of a solar, astral, or
other foreign nature; on account of which the air is so necessary to the
substance of flame!" It was this idea that attracted the attention
of George Ernst Stahl (1660-1734), a professor of medicine in the
University of Halle, who later founded his new theory upon it. Stahl's
theory was a development of an earlier chemist, Johann Joachim Becker
(1635-1682), in whose footsteps he followed and whose experiments he
carried further.

In many experiments Stahl had been struck wit