and then, for a brief period, these peaceful
vocations would be wholly suspended and set aside by a revolt or by a
civil war, waged by rival brothers against each other, or instigated by
the conflicting claims of a mother and son. These interruptions,
however, were comparatively few, and, in ordinary cases, not of long
continuance. It was for the interest of all branches of the royal line
to do as little injury as possible to the commercial and agricultural
operations of the realm. In fact, it was on the prosperity of those
operations that the revenues depended. The rulers were well aware of
this, and so, however implacably two rival princes may have hated one
another, and however desperately each party may have struggled to
destroy all active combatants whom they should find in arms against
them, they were both under every possible inducement to spare the
private property and the lives of the peaceful population. This
population, in fact, engaged thus in profitable industry, constituted,
with the avails of their labors, the very estate for which the
combatants were contending.

Seeing the subject in this light, the Egyptian sovereigns, especially
Alexander and the earlier Ptolemies, made every effort in their power to
promote the commercial greatness of Alexandria. They built palaces, it
is true, but they also built warehouses.

One of the most expensive and celebrated of all the edifices that they
reared was the light-house which has been already alluded to. This
light-house was a lofty tower, built of white marble. It was situated
upon the island of Pharos, opposite to the city, and at some distance
from it. There was a sort of isthmus of shoals and sand-bars connecting
the island with the shore. Over these shallows a pier or causeway was
built, which finally became a broad and inhabited neck. The principal
part of the ancient city, however, was on the main land.

The curvature of the earth requires that a light-house on a coast should
have a considerable elevation, otherwise its summit would not appear
above the horizon, unless the mariner were very near. To attain this
elevation, the architects usually take advantage of some hill or cliff,
or rocky eminence near the shore. There was, however, no opportunity to
do this at Pharos; for the island was, like the main land, level and
low. The requisite elevation could only be attained, therefore, by the
masonry of an edifice, and the blocks of marble necessary for the