Page:Popular Science Monthly Volume 22.djvu/809

Rh such facts as we gain; while, without facts, we can not improve our hypothesis.

The great trouble about matter is to find out how much of it and what in it is material. Strange to say, there is nothing on which philosophers are less agreed. Unfortunately, our notions of matter are derived solely from sense impressions; and that form of it which most impresses the senses is the most encumbered with fugitive and non-essential properties. We can not say with certainty whether these properties are positive or negative.

When upon a clear summer's day we gaze outward into a cloudless sky, we look apparently into clear and void space, except for the deep blue diffused light. We recognize vacuity. Even while we gaze, perhaps a light, fleecy cloud forms itself before our eyes, and we form the concept of the creation of a material object. We know that it is not a mere apparition—it is a form of substance. Properties begin to be recognizable in it. It reflects light—it displays color—it moves. Should its development progress, we shall have still further evidence of its substantiality. It will grow darker and more dense. It will exhibit gravity, and descend in liquid drops or solid flakes, and these portions in turn will exhibit the typical properties, qualities, and reactions of matter.

Now, what elicited this bundle of realities out of apparent nothing? A mere local refrigeration—a flaw of nothing tangible—abstracted something from the invisible potential occupant of the space, reduced its volume, sapped its mobility, its power of holding its own, and properties began to appear. Death began its work, and, as the animus fled, the skeleton framework came within our ken.

We might rise by analogy from the nimbus to the nebula—from the terrestrial to the cosmical—and see with imagination's eye a similar inverse evolution producing the apparition of things substantial, which may be really but the intaglio of the realities. For that which consists merely in the negation of something can not be the truest substance. An ulcer is not more material or real than the healthy tissue before the latter gives urgent call for recognition of its actuality by inflammation, incipient degradation, and advancing dissolution.

It may be possible, however, to corner a reality by the reverse process. A fair type of matter is our block of ice. It is sufficiently substantial, and loaded down with properties. A simple exposure to different temperature conditions causes its sensational properties to drop off like old clothes. We soon come to a pair of invisible and intangible existences, investigable by indirect means only, of which sufficient knowledge has been gained to establish their discontinuous or corpuscular character, as imagined by Democritus.

This molecule we must take as the representative of matter; for all masses of it, whether gaseous, liquid, or solid, are but aggregations of similar corpuscles. We can only pursue it with the eye of the