ledge. Many and important portions of this knowledge, both as
regards the phenomena of the celestial spaces and those belonging to our
own planet, are already based on foundations too firm to be lightly
shaken; although in other portions general laws will doubtless take the
place of those which are more limited in their application, new forces
will be discovered, and substances considered as simple will be
decomposed, while others will become known.

JAMES HUTTON

The Theory of the Earth

James Hutton, the notable Scotch geologist, was born at Edinburgh
on June 3, 1726. In 1743 he was apprenticed to a Writer to the
Signet; but his apprenticeship was of short duration and in the
following year he began to study medicine at Edinburgh University,
and in 1749 graduated as an M.D. Later he determined to study
agriculture, and went, in 1752, to live with a Norfolk farmer to
learn practical farming. He did not devote himself entirely to
agriculture, but gave a considerable amount of his time to chemical
and geological researches. His geological researches culminated in
his great work, "The Theory of the Earth," published at Edinburgh
in 1795. In this work he propounds the theory that the present
continents have been formed at the bottom of the sea by the
precipitation of the detritus of former continents, and that the
precipitate had been hardened by heat and elevated above the sea by
the expansive power of heat. He died on March 26, 1797. Other works
are his "Theory of Rain," "Elements of Agriculture," "Natural
Philosophy," and "Nature of Coal."

_I.--Origin and Consolidation of the Land_

The solid surface of the earth is mainly composed of gravel, of
calcareous, and argillaceous strata. Sand is separated by streams and
currents, gravel is formed by the attrition of stones agitated in water,
and argillaceous strata are deposited by water containing argillaceous
material. Accordingly, the solid earth would seem to have been mainly
produced by water, wind, and tides, and this theory is confirmed by the
discovery that all the masses of marble and limestone are composed of
the calcareous matter of marine bodies. All these materials were, in the
first place, deposited at the bottom of the sea, and we have to
consider, firstly, how they were consolidated; and secondly, how they
came to be dry land, elevated above the sea.

It is pla