al habit of thought and accommodation of theory to the
actual purposes of life pre-eminently required by their profession,
leads them spontaneously to decline speculative uncertainties, and to be
satisfied only with things that are real and exact.

[Sidenote: The great men it produced.]

Under the inspiration of the system of Alexander, and guided by the
suggestions of certain great men who had caught the spirit of the times,
the Egyptian kings thus created, under their own immediate auspices, the
Museum. State policy, operating in the manner I have previously
described, furnished them with an additional theological reason for
founding this establishment. In the Macedonian campaign a vast amount of
engineering and mathematical talent had been necessarily stimulated into
existence, for great armies cannot be handled, great marches cannot be
made, nor great battles fought without that result. When the period of
energetic action was over, and to the military operations succeeded
comparative repose and temporary moments of peace, the talent thus
called forth found occupation in the way most congenial to it by
cultivating mathematical and physical studies. In Alexandria, itself a
monument of engineering and architectural skill, soon were to be found
men whose names were destined for futurity--Apollonius, Eratosthenes,
Manetho. Of these, one may be selected for the remark that, while
speculative philosophers were occupying themselves with discussions
respecting the criterion of truth, and, upon the whole, coming to the
conclusion that no such thing existed, and that, if the truth was
actually in the possession of man, he had no means of knowing it, Euclid
of Alexandria was writing an immortal work, destined to challenge
contradiction from the whole human race, and to make good its title as
the representative of absolute and undeniable truth--truth not to be
gainsaid in any nation or at any time. We still use the geometry of
Euclid in our schools.

[Sidenote: The writings of Euclid.]

It is said that Euclid opened a geometrical school in Alexandria about
B.C. 300. He occupied himself not only with mathematical, but also with
physical investigation. Besides many works of the former class supposed
to have been written by him, as on Fallacies, Conic Sections, Divisions,
Porisms, Data, there are imputed to him treatises on Harmonics, Optics,
and Catoptrics, the two latter subjects being discussed, agreeably to
the views of tho