||One might naturally
suppose that the science of the earth which lies at man's feet would at
least have kept pace with the science of the distant stars. But perhaps
the very obviousness of the phenomena delayed the study of the crust of
the earth. It is the unattainable that allures and mystifies and enchants
the developing mind. The proverbial child spurns its toys and cries for
So in those closing days of the eighteenth
century, when astronomers had gone so far towards explaining the mysteries
of the distant portions of the universe, we find a chaos of opinion regarding
the structure and formation of the earth. Guesses were not wanting to explain
the formation of the world, it is true, but, with one or two exceptions,
these are bizarre indeed. One theory supposed the earth to have been at
first a solid mass of ice, which became animated only after a comet had
dashed against it. Other theories conceived the original globe as a mass
of water, over which floated vapors containing the solid elements, which
in due time were precipitated as a crust upon the waters. In a word, the
various schemes supposed the original mass to have been ice, or water,
or a conglomerate of water and solids, according to the random fancies
of the theorists; and the final separation into land and water was conceived
to have taken place in all the ways which fancy, quite unchecked by any
tenable data, could invent.
Whatever important changes in the general
character of the surface of the globe were conceived to have taken place
since its creation were generally associated with the Mosaic: deluge, and
the theories which attempted to explain this catastrophe were quite on
a par with those which dealt with a remoter period of the earth's history.
Some speculators, holding that the interior of the globe is a great abyss
of waters, conceived that the crust had dropped into this chasm and had
thus been inundated. Others held that the earth had originally revolved
on a vertical axis, and that the sudden change to its present position
bad caused the catastrophic shifting of its oceans. But perhaps the favorite
theory was that which supposed a comet to have wandered near the earth,
and in whirling about it to have carried the waters, through gravitation,
in a vast tide over the continents.
Thus blindly groped the majority of eighteenth-century
philosophers in their attempts to study what we now term geology. Deluded
by the old deductive methods, they founded not a science, but the ghost
of a science, as immaterial and as unlike anything in nature as any other
phantom that could be conjured from the depths of the speculative imagination.
And all the while the beckoning earth lay beneath the feet of these visionaries;
but their eyes were fixed in air.
At last, however, there came a man who
had the penetration to see that the phantom science of geology needed before
all else a body corporeal, and who took to himself the task of supplying
it. This was Dr. James Hutton, of Edinburgh, physician, farmer, and manufacturing
chemist - patient, enthusiastic, level-headed devotee of science. Inspired
by his love of chemistry to study the character of rocks and soils, Hutton
had not gone far before the earth stood revealed to him in a new light.
He saw, what generations of predecessors had blindly refused to see, that
the face of nature everywhere, instead of being rigid and immutable, is
perennially plastic, and year by year is undergoing metamorphic changes.
The solidest rocks are day by day disintegrated slowly, but none the less
surely, by wind and rain and frost, by mechanical attrition and chemical
decomposition, to form the pulverized earth and clay. This soil is being
swept away by perennial showers, and carried off to the oceans. The oceans
themselves beat on their shores, and eat insidiously into the structure
of sands and rocks. Everywhere, slowly but surely, the surface of the land
is being worn away; its substance is being carried to burial in the seas.
Should this denudation continue long enough,
thinks Hutton, the entire surface of the continents must be worn away.
Should it be continued LONG ENOUGH! And with that thought there flashes
on his mind an inspiring conception - the idea that solar time is long,
indefinitely long. That seems a simple enough thought - almost a truism
- to the twentieth-century mind; but it required genius to conceive it
in the eighteenth. Hutton pondered it, grasped its full import, and made
it the basis of his hypothesis, his "theory of the earth."