implements showing cultures are throwing
new light on the science of man and indicating a continuous development
from very primitive beginnings.

_Progress Is Indicated by the Early Cultures_.--It is convenient to
divide the early culture of man, based upon his development in art into
the Paleolithic, or unpolished, and the Neolithic, or polished, Stone
Ages.[2] The former is again divided into the Eolithic, Lower
Paleolithic, and the Upper Paleolithic. In considering these divisions
of relative time cultures, it must be remembered that the only way we
have of measuring prehistoric time is through the geological method,
based upon the Ice Ages and changes in the physical contour of the
earth.

In the strata of the earth, either in the late second inter-glacial
period or at the beginning of the third, chipped rocks, or eoliths, are
found used by races of which the Piltdown and Heidelberg species are
representatives.[3] Originally man used weapons to hammer and to cut
already prepared by nature. Sharp-edged flints formed by the crushing
of rocks in the descent of the glaciers or by upheavals of earth or by
powerful torrents were picked up as needed for the purpose of cutting.
Wherever a sharp edge was needed, these natural implements were useful.
Gradually man learned to carry the best specimens with him. These he
improved by chipping the edges, making them more serviceable, or
chipping the eolith, so as to grasp it more easily. This represents
the earliest relic of the beginning of civilization through art.
Eoliths of this kind are found in Egypt in the hills bordering the Nile
Valley, in Asia and America, as well as in southern Europe. Perhaps at
the same period of development man selected stones suitable for
crushing bones or for other purposes when hammering {31} was necessary.
These were gradually fashioned into more serviceable hammers. In the
latter part of this period, known as the pre-Chellean, flint implements
were considerably improved.

In the Lower Paleolithic in the pre-Neanderthal period, including what
is known as the Chellean, new forms of implements are added to the
earlier beginnings. Almond-shaped flint implements, followed later by
long, pointed implements, indicate the future development of the stone
spear, arrowhead, knife, and axe. Also smaller articles of use, such
as borers, scrapers, and ploughs, appeared. The edges of all
implements were rough and uneven, and the forms very imper