solstice of the year B.C. 432. by Meton and Euctemon. We have,
for the first time, in that school, a combined system of
observations made with instruments for the measurement of angles,
and calculated by trigonometrical methods. Astronomy then took a
form which subsequent ages could only perfect.


It does not accord with the compass or the intention of this work
to give a detailed account of the contributions of the
Alexandrian Museum to the stock of human knowledge. It is
sufficient that the reader should obtain a general impression of
their character. For particulars, I may refer him to the sixth
chapter of my "History of the Intellectual Development of
Europe."

EUCLID--ARCHIMEDES. It has just been remarked that the Stoical
philosophy doubted whether the mind can ascertain absolute truth.
While Zeno was indulging in such doubts, Euclid was preparing his
great work, destined to challenge contradiction from the whole
human race. After more than twenty-two centuries it still
survives, a model of accuracy, perspicuity, and a standard of
exact demonstration. This great geometer not only wrote on other
mathematical topics, such as Conic Sections and Porisms, but
there are imputed to him treatises on Harmonics and Optics, the
latter subject being discussed on the hypothesis of rays issuing
from the eye to the object.

With the Alexandrian mathematicians and physicists must be
classed Archimedes, though he eventually resided in Sicily. Among
his mathematical works were two books on the Sphere and Cylinder,