sen remarks, from the known
portion of the curve of history we may determine the whole. The
Egyptians, old as they are, belong to the middle ages of mankind, for
there is a period antecedent to monumental history, or indeed, to
history of any kind, during which language and mythology are formed, for
these must exist prior to all political institutions, all art, all
science. Even at the first moment that we gain a glimpse of the state of
Egypt she had attained a high intellectual condition, as is proved by
the fact that her system of hieroglyphics was perfected before the
fourth dynasty. It continued unchanged until the time of Psammetichus. A
stationary condition of language and writing for thousands of years
necessarily implies a long and very remote period of active improvement
and advance. It was doubtless such a general consideration, rather than
a positive knowledge of the fact, which led the Greeks to assert that
the introduction of geometry into Egypt must be attributed to kings
before the times of Menes. Not alone do her artificial monuments attest
for that country an extreme antiquity; she is herself her own witness;
for, though the Nile raises its bed only four feet in a thousand years,
all the alluvial portion of Egypt has been deposited from the waters of
that river. A natural register thus re-enforces the written records, and
both together compose a body of evidence not to be gainsaid. Thus the
depth of muddy silt accumulated round the pedestals of monuments is an
irreproachable index of their age. In the eminent position he occupied,
Eusebius might succeed in perverting the received book-chronology; but
he had no power to make the endless trade-wind that sweeps over the
tropical Pacific blow a day more or a day less; none to change the
weight of water precipitated from it by the African mountains; none to
arrest the annual mass of mud brought down by the river. It is by
collating such different orders of evidence together--the natural and
the monumental, the latter gaining strength every year from the
cultivation of hieroglyphic studies--that we begin to discern the true
Egyptian chronology, and to put confidence in the fragments that remain
of Eratosthenes and Manetho.

[Sidenote: Astronomy of Eratosthenes.]

[Sidenote: Attempts of Aristarchus to find the distance of the sun.]

At the time of which we are speaking--the time of Eratosthenes--general
ideas had been attained to respecting the doctrine of t