nded on the
solid rock.

An appeal to the imagination is much more alluring than the employment
of reason. In the intellectual decline of Alexandria, indolent methods
were preferred to laborious observation and severe mental exercise. The
schools of Neo-Platonism were crowded with speculative mystics, such
as Ammonius Saccas and Plotinus. These took the place of the severe
geometers of the old Museum.

PHYSICAL SCIENCE IN THE MUSEUM. The Alexandrian school offers the first
example of that system which, in the hands of modern physicists, has
led to such wonderful results. It rejected imagination, and made its
theories the expression of facts obtained by experiment and observation,
aided by mathematical discussion. It enforced the principle that the
true method of studying Nature is by experimental interrogation. The
researches of Archimedes in specific gravity, and the works of
Ptolemy on optics, resemble our present investigations in experimental
philosophy, and stand in striking contrast with the speculative vagaries
of the older writers. Laplace says that the only observation which the
history of astronomy offers us, made by the Greeks before the school
of Alexandria, is that of the summer 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 lat