he records of which constitute our first introduction to the so-called
historical period. Taken somewhat in the order of their probable
discovery, the scientific ideas of primitive man may be roughly listed
as follows:

1. Primitive man must have conceived that the earth is flat and of
limitless extent. By this it is not meant to imply that he had a
distinct conception of infinity, but, for that matter, it cannot be said
that any one to-day has a conception of infinity that could be called
definite. But, reasoning from experience and the reports of travellers,
there was nothing to suggest to early man the limit of the earth. He
did, indeed, find in his wanderings, that changed climatic conditions
barred him from farther progress; but beyond the farthest reaches of
his migrations, the seemingly flat land-surfaces and water-surfaces
stretched away unbroken and, to all appearances, without end. It would
require a reach of the philosophical imagination to conceive a limit
to the earth, and while such imaginings may have been current in the
prehistoric period, we can have no proof of them, and we may well
postpone consideration of man's early dreamings as to the shape of the
earth until we enter the historical epoch where we stand on firm ground.

2. Primitive man must, from a very early period, have observed that the
sun gives heat and light, and that the moon and stars seem to give light
only and no heat. It required but a slight extension of this observation
to note that the changing phases of the seasons were associated with the
seeming approach and recession of the sun. This observation, however,
could not have been made until man had migrated from the tropical
regions, and had reached a stage of mechanical development enabling him
to live in subtropical or temperate zones. Even then it is conceivable
that a long period must have elapsed before a direct causal relation was
felt to exist between the shifting of the sun and the shifting of the
seasons; because, as every one knows, the periods of greatest heat in
summer and greatest cold in winter usually come some weeks after the
time of the solstices. Yet, the fact that these extremes of temperature
are associated in some way with the change of the sun's place in the
heavens must, in time, have impressed itself upon even a rudimentary
intelligence. It is hardly necessary to add that this is not meant
to imply any definite knowledge of the real meaning of, the seeming
os