sisted, in reply
to Dick's incredulous shrug of the shoulders, "otherwise they would not
gleam so brilliantly in the sun as they do. And to-morrow night, please
God, we will rest our weary limbs in that same city, and perhaps, if
luck is with us, make the acquaintance of El Dorado himself, or at all
events, his successor."

CHAPTER TWELVE.

GUESTS--OR PRISONERS?

The camp was astir with the coming of dawn on the following morning; and
after an early breakfast the expedition started, under Dick's guidance,
for the gateway, which was reached shortly before noon. As the party
approached, the sentinel was seen pacing to and fro across the parapet,
as on the preceding afternoon; and that he was keeping a sharp look-out
was manifest, for the little band had scarcely emerged from the pine
wood in which Dick had halted for his mid-day meal on the preceding day,
when the man was seen to pause in his monotonous march to and fro and
gaze toward them under the shadow of his hand. Then, apparently
satisfied that the party were bound for the gateway, he was seen to move
a few paces and bend over, with his hand to his mouth, as though
shouting to someone below, after which he resumed his march as before,
occasionally eyeing the strangers as they approached.

Arrived at length at the gateway, it was seen that the structure
consisted of a wall, some thirty feet high, very solidly built of great
blocks of masonry dressed to a perfectly smooth face, and so accurately
jointed that, even at the distance of a few paces, the joints were
scarcely perceptible. The wall was built with a vertical face to a
height of some twenty feet, above which it swelled outward in the form
known as a "bull-nose," the upper surface of which sloped so steeply
upward as to render it unclimbable; so that, even if a man, or men,
should climb as far as the swell of the bull-nose by means of a pole or
ladder, the would-be intruders could get no farther. The wall was
semi-circular in plan, jutting out from the edge of the cliff for a
distance of some fifteen feet at either end and descending the face of
the cliff, diminishing as it went, until it died away to nothing, some
fifty feet below, rendering it an impossibility for anyone to pass round
either end of it. The middle of the wall was so constructed as to form
a watch-tower, some thirty feet square, with a flat roof, upon which it
appeared a sentinel was always posted; and it was in the base of the