ose his position.
He found such a field in an extensive plain at Guagamela, not far from
the city of Arbela. The spot has received historical immortality under
the name of the plain of Arbela.

Darius was several days in concentrating his vast armies upon this
plain. He constructed encampments; he leveled the inequalities which
would interfere with the movements of his great bodies of cavalry; he
guarded the approaches, too, as much as possible. There is a little
instrument used in war called a _caltrop_.[E] It consists of a small
ball of iron, with several sharp points projecting from it one or two
inches each way. If these instruments are thrown upon the ground at
random, one of the points must necessarily be upward, and the horses
that tread upon them are lamed and disabled at once. Darius caused
caltrops to be scattered in the grass and along the roads, wherever
the army of Alexander would be likely to approach his troops on the
field of battle.

[Footnote E: It receives its name from a kind of thistle called the
caltrop.]

[Illustration: THE CALTROP.]

Alexander, having crossed the river, encamped for a day or two on the
banks, to rest and refresh, and to rearrange his army. While here, the
soldiers were one night thrown into consternation by an eclipse of the
moon. Whenever an eclipse of the moon takes place, it is, of course,
when the moon is full, so that the eclipse is always a sudden, and,
among an ignorant people, an unexpected waning of the orb in the
height of its splendor; and as such people know not the cause of the
phenomenon, they are often extremely terrified. Alexander's soldiers
were thrown into consternation by the eclipse. They considered it the
manifestation of the displeasure of Heaven at their presumptuous
daring in crossing such rivers, and penetrating to such a distance to
invade the territories of another king.

In fact, the men were predisposed to fear. Having wandered to a vast
distance from home, having passed over such mountains and deserts, and
now, at last, having crossed a deep and dangerous river, and thrown
themselves into the immediate vicinity of a foe ten times as numerous
as themselves, it was natural that they should feel some misgivings.
And when, at night, impressed with the sense of solemnity which night
always imparts to strange and novel scenes, they looked up to the
bright round moon, pleased with the expression of cheerfulness and
companionship which beams always i