ecian isles.
In his youth he came in contact with THALES--the Father of Geometry,
as he is well called,--and though he did not become a member of THALES'
school, his contact with the latter no doubt helped to turn his mind
towards the study of geometry. This interest found the right ground for
its development in Egypt, which he visited when still young. Egypt is
generally regarded as the birthplace of geometry, the subject having, it
is supposed, been forced on the minds of the Egyptians by the necessity
of fixing the boundaries of lands against the annual overflowing of the
Nile. But the Egyptians were what is called an essentially practical
people, and their geometrical knowledge did not extend beyond a few
empirical rules useful for fixing these boundaries and in constructing
their temples. Striking evidence of this fact is supplied by the AHMES
papyrus, compiled some little time before 1700 B.C. from an older
work dating from about 3400 B.C.,(1) a papyrus which almost certainly
represents the highest mathematical knowledge reached by the Egyptians
of that day. Geometry is treated very superficially and as of subsidiary
interest to arithmetic; there is no ordered series of reasoned
geometrical propositions given--nothing, indeed, beyond isolated rules,
and of these some are wanting in accuracy.

(1) See AUGUST EISENLOHR: _Ein mathematisches Handbuch der alten
Aegypter_ (1877); J. Gow: _A Short History of Greek Mathematics_ (1884);
and V. E. JOHNSON: _Egyptian Science from the Monuments and Ancient
Books_ (1891).

One geometrical fact known to the Egyptians was that if a triangle be
constructed having its sides 3, 4, and 5 units long respectively, then
the angle opposite the longest side is exactly a right angle; and the
Egyptian builders used this rule for constructing walls perpendicular to
each other, employing a cord graduated in the required manner. The
Greek mind was not, however, satisfied with the bald statement of mere
facts--it cared little for practical applications, but sought above all
for the underlying REASON of everything. Nowadays we are beginning to
realise that the results achieved by this type of mind, the general laws
of Nature's behaviour formulated by its endeavours, are frequently
of immense practical importance--of far more importance than the mere
rules-of-thumb beyond which so-called practical minds never advance.
The classic example of the utility of seemingly useless knowledge is
aff