est river, lake, and lagoon navigation. In the latest
specifications the engineers proposed to dam up the river (San Juan) by
a stone wall seventy feet high and 1,900 feet long, thus raising the
water to a level of 106 feet above the sea. Only three locks will be
required to work the Nicaraguan Ship-canal.

CHAPTER IX

EXTINCT CIVILIZATION OF PERU

Sec. (A) _Peruvian Archeology_

As the extinct civilization of the Incas of Peru is the most important
phase of development among all the American races, so also their
prehistoric remains are extremely interesting to the archeologist.

[Illustration: Monolith Doorway. Near Lake Titicaca. Fig. 1.]

1. _Architecture._--In the interior of the country we find many
remarkable examples of stone building, such as walls of huge polygonal
stones, four-sided or five-sided or six-sided, some six feet across,
laid without mortar, and so finely polished and adjusted that the blade
of a knife can not be inserted between them. The strength of the masonry
is sometimes assisted by having the projecting parts of a stone fitting
into corresponding hollows or recesses in the stone above or below it.
The stones being frequently extremely hard granite, or basalt, etc.,
antiquarian travelers have wondered how in early times the natives could
have cut and polished them without any metal tools. The ordinary
explanation is that the work was done by patiently rubbing one stone
against another, with the aid of sharp sand, "time being no object" in
the case of the laborers among savage and primitive races. It is
believed by most antiquaries that long before the period of the Incas
there was a powerful empire to which we must attribute such Cyclopean
ruins; especially as the construction and style differ so greatly from
what is found in the Inca period. The huge stones occur at Tiahuanacu
(near Lake Titicaca), Cuzco, Ollantay, and the altar of Concacha. Fig. 1
is a broken doorway at Tiahuanacu, composed of huge monoliths. Fig. 2 is
an enlargement of an image over the doorway shown in Fig. 1. The doorway
forms the entrance to a quadrangular area (400 yards by 350) surrounded
by large stones standing on end. The gateway or doorway of Fig. 1 is one
of the most marvelous stone monuments existing, being _one block of hard
rock_, deeply sunk in the ground. The present height is over seven feet.
The whole of the inner side "from a line level with the upper lintel of
the doorway to the top" is a mas