previous generation of men had even the slightest inkling.

All in all, then, those that lie before us are perhaps the most
wonderful and the most fascinating of all the fields of science.
As the chapters of the preceding book carried us out into a
macrocosm of inconceivable magnitude, our present studies are to
reveal a microcosm of equally inconceivable smallness. As the
studies of the physicist attempted to reveal the very nature of
matter and of energy, we have now to seek the solution of the yet
more inscrutable problems of life and of mind.



I. THE PHLOGISTON THEORY IN CHEMISTRY

The development of the science of chemistry from the "science" of
alchemy is a striking example of the complete revolution in the
attitude of observers in the field of science. As has been
pointed out in a preceding chapter, the alchemist, having a
preconceived idea of how things should be, made all his
experiments to prove his preconceived theory; while the chemist
reverses this attitude of mind and bases his conceptions on the
results of his laboratory experiments. In short, chemistry is
what alchemy never could be, an inductive science. But this
transition from one point of view to an exactly opposite one was
necessarily a very slow process. Ideas that have held undisputed
sway over the minds of succeeding generations for hundreds of
years cannot be overthrown in a moment, unless the agent of such
an overthrow be so obvious that it cannot be challenged. The
rudimentary chemistry that overthrew alchemy had nothing so