f hideous depth were filled up with solid
masonry; in short, all the difficulties that beset a wild and
mountainous region, and which might appall the most courageous engineer
of modern times, were encountered and successfully overcome. Stone
pillars in the manner of European milestones were erected at stated
intervals of somewhat more than a league all along the route. Its
breadth scarcely exceeded twenty feet. It was built of heavy flags of
freestone, and in some parts, at least, covered with a bituminous
cement, which time has made harder than the stone itself. In some
places where the ravines had been filled up with masonry, the mountain
torrents, wearing on it for ages, have gradually eaten a way through
the base, and left the superincumbent mass--such is the cohesion of the
materials--still spanning the valley like an arch.

"Another great road of the Incas lay through the level country between
the Andes and the ocean. It was constructed in a different manner, as
demanded by the nature of the ground, which was for the most part low,
and much of it sandy. The causeway was raised on a high embankment of
earth, and defended on either side by a parapet or wall of clay; and
trees and odoriferous shrubs were planted along the margin, regaling
the sense of the traveller with their perfume, and refreshing him by
their shades, so grateful under the burning sky of the tropics.

"The care of the great roads was committed to the districts through
which they passed, and a large number of hands was constantly employed
to keep them in repair. This was the more easily done in a country
where the mode of travelling was altogether on foot; though the roads
are said to have been so nicely constructed that a carriage might have
rolled over them as securely as on any of the great roads of Europe.
Still, in a region where the elements of fire and water are both
actively at work in the business of destruction, they must without
constant supervision have gradually gone to decay. Such has been their
fate under the Spanish conquerors, who took no care to enforce the
admirable system for their preservation adopted by the Incas. Yet the
broken portions that still survive here and there, like the fragments
of the great Roman roads scattered over Europe, bear evidence of their
primitive grandeur, and have drawn forth eulogium from the
discriminating traveller; for Humboldt, usually not profuse in his
panegyrics, says, 'The roads of the Incas