between the Cyclopean structures already
described and the Inca architecture. The chief part is 110 yards long,
built of wrought stones; and in the middle of the building from end to
end runs a wall pierced by twelve high doorways. There were also two
series of pillars which had formerly supported a floor.

Those traces of the Cyclopean builders point to an extremely early date,
but several students of the Peruvian antiquities point confidently to
distinct evidence of a still more primitive race--to be compared,
perhaps, with those builders of "Druidic monuments" whom it is now the
fashion to call "neolithic men." Some "cromlechs" or burial-places have
been found in Bolivia and other parts of Peru; and in many respects they
are parallel to the stone monuments found in Great Britain as well as
Brittany and other parts of Europe. Some of those Peruvian cromlechs
consist of four great slabs of slate, each about five feet high, four or
five in width, and more than an inch thick. A fifth is placed over them.
Over the whole a pyramid of clay and rough stones is piled. Possibly
that race of cromlech builders bore the same relation to the temple
builders described above that the builders of Kits Coty House, between
Rochester and Maidstone, bore to the temple builders of Stonehenge on
Salisbury Plain. If they had to retreat, as the ice-sheet was driven
farther from the torrid zone, then by the theory of the Glacial Period
the Cromlech men in both cases would at last be simply Eskimos.

2. _Aqueducts._--The ancient Peruvians attained great skill in the
distribution of water--especially for irrigation. Artificial lakes or
reservoirs were formed, so that by damming up the streams in the rainy
season a good supply was created for the dry season. Some great
monuments still remain of their hydraulic engineering, such as extensive
cisterns, solid dikes along the rivers to prevent overflow, tunnels to
drain lakes during an oversupply, and, in some places, artificial
cascades.

3. _Roads and Bridges._--The roads and highways of the Incas were so
excellent that "in many places" they still offer by far the most
convenient avenues of transit. They are from fifteen to twenty-five feet
in width, bedded with small stones often laid in concrete. As the use of
beasts of burden was almost unknown, the roads did not ascend a steep
inclination by zigzags but by steps cut in the rock. At certain
distances public shelters were erected for traveler