then look at the middle-aged man; you will find him burnt by
the sun, tanned by wind and weather to a dark brown which will not
bleach off even should he return to his native northern country to live.
His children will be born darker than he was, his grandchildren probably
darker still, and so on. What, then, must be the change should the
descendants of a particular set of men live thousands--not hundreds, but
thousands--of years in one particular zone of the earth, under the same
conditions of climate, food, and local nature generally--what we call
"environment"?

This is exactly what happened to those detachments which once upon a
time separated from the original human family. Each may have gone forth
at random, but there was the earth to choose from and to be had for the
taking; and, wherever such a detachment settled, there was nothing to
prevent its posterity staying on and on, and developing their own
peculiarities under local influences; for it would take many, many
centuries before there would again be a lack of room and the process of
separation would be repeated. Thus were formed the subdivisions of the
human kind, with their striking characteristics and distinctive
peculiarities, which we call the great Races of the World.

Now, if this thing were to happen to any one of us--that we should
discover brothers and kinsfolk of whom we knew nothing before--we would
be very curious to find out all we could about them: where they came
from, what had happened to them during all those years until they
settled where we found them, and when and why they separated from their
forefathers, who were also our own. These are the very things we want to
find out about the various nations who live in the world now, and those
who have lived in it before anything existed of what is now in the
world, all the way back to the beginning.

The task is quite easy, so long as we have books to help us, histories
to tell us year by year all that went on in every part of the Great
Round World, as our newspapers tell us day by day what is going on in it
now. But books do not take us very far back. It is only four hundred
years since printing was invented, and not more than six hundred since
the art of making paper out of rags has been known. But people could
write hundreds and hundreds of years before that was invented, and used
almost anything to record the memorable doings of their day--bark of
trees, skins of animals (parchment), "papyr