untain slopes had become a garden, immense terraces having been
constructed wherever required, and irrigation on a grander scale than
that of Egypt carried on by gigantic canals and aqueducts. Advantage was
taken of the different mean annual temperatures at different altitudes
to pursue the cultivation of various products, for difference in height
topographically answers to difference in latitude geographically, and
thus, in a narrow space, the Peruvians had every variety of temperature,
from that corresponding to the hottest portions of Southern Europe to
that of Lapland. In the mountains of Peru, as has been graphically said,
man sees "all the stars of the heavens and all the families of plants."
On plateaus at a great elevation above the sea there were villages and
even cities. Thus the plain upon which Quito stands, under the equator,
is nearly ten thousand feet high. So great was their industry that the
Peruvians had gardens and orchards above the clouds, and on ranges still
higher flocks of lamas, in regions bordering on the limit of perpetual
snow.

[Sidenote: Its great roads and engineering,] Through the entire length
of the empire two great military roads were built, one on the plateau,
the other on the shore. The former, for nearly two thousand miles,
crossed sierras covered with snow, was thrown over ravines, or went
through tunnels in the rocks; it scaled the more difficult precipices by
means of stairways. Where it was possible, it was carried over the
mountain clefts by filling them with masonry, or, where that could not
be done, suspension bridges were used, the cables being made of osiers
or maguey fibres. Some of these cables are said to have been as thick as
a man, and two hundred feet long. Where such bridges could not be thrown
across, and a stream flowed in the bottom of the mountain valley, the
passage was made by ferry-boats or rafts. As to the road itself, it was
about twenty feet in width, faced with flags covered with bitumen, and
had mile-stones. Our admiration at this splendid engineering is enhanced
when we remember that it was accomplished without iron and gunpowder.
The shore road was built on an embankment, with a clay parapet on each
side, and shade trees. Where circumstances called for it, piles were
used. [Sidenote: and expresses by couriers.] Every five miles there was
a post-house. The public couriers, as in Mexico, could make, if
necessary, two hundred miles a day. Of these roads Hum