Physical geography. By Mary Somerville ...

480 PHYSICAL GEOGRAPHY. CHAP. XXXIII
of time antecedent to the Christian period must have made it
shorter.'
Darkness of complexion has been attributed to the sun's power
from the age of Solomon to this day-" Look not upon me, because
I am black, because the sun hath looked upon me;" and there can
be no doubt that, to a certain degree, the opinion is well founded.
The invisible rays of the solar beams, which change vegetable
colours, and have been employed with such remarkable effect in the
Daguerreotype, act upon every substance on which they fall, producing mysterious and wonderful changes in their molecular stateman not excepted.2
Other causes must have been combined to occasion all the varieties we now see, otherwise every nation between the tropics would
be of the same hue, whereas the sooty Negro inhabits equatorial
Africa, the Red man equinoctial America, and both are mixed with
fairer tribes. In Asia, the Rohillas, a fair race of Affghan extraction, inhabit the plains north of the Ganges; the Bengalee and the
mountaineers of Nepaul are dark, and the Mahrattas are yellow.
The complexion of man varies with height and latitude; some of
the inhabitants of the Himalaya and Hindoo Koosh are fair, and
even a red-haired race is found on the latter. There are fair-haired
people with blue eyes in the Ruddhua mountains in Africa. The
Kabyles, that inhabit the country behind Tunis and Algiers, are
similar in complexion to the nations in high northern latitudes.
This correspondence, however, only maintains with regard to the
northern hemisphere, for it is a well-known fact that the varieties
of the numerous species in the great southern continents are much
From the discrepancies in the chronological systems, it is evident that
the actual period of man's creation is not accurately known. The Chevalier Bunsen has ascertained from monumental inscriptions, that the successive Egyptian dynasties may be traced back to Meres, 3640 years before
the Christian era, and from the high state of civilization during the reign
of that prince, proved by the magnificence of the works then executed, he
infers that the Egyptians must have existed 500 years previous to their
consolidation into one empire by him, which goes back to the received
period of man's creation. Compared with geological periods, man is of
very recent creation, as appears from the vast extent of uninhabited land,
but which would require ages and ages to people, even if the increase of
population were as rapid as in the United States of North America. Dr.
Pritchard says that the Hebrew chronology has been computed with some
approximation to truth up to the arrival of Abraham in Palestine, but that
we can never know how many centuries may have elapsed from that event
to the time when " the first man of clay received the image of God and the
breath of life."
2 Dark-coloured substances absorb more of the sun's heat than light,
coloured ones; therefore, the black skins of the natives of tropical climates
absorb more heat than fair skins; but, from some unknown cause, the
black skin is protected from a degree of heat that would blister a fair one.