int; for Pio
soon rose, walked to the side of the chamber exactly opposite the
stairs, whistled shrilly, as before, and an aperture immediately
manifested itself, large enough to admit the body of a man! Through this
he crawled, and beckoned me to follow. No sooner had I crept through the
wall, than the stone dropped from above, and closed the orifice
completely. I now found myself standing erect in what appeared to be a
subterranean aqueduct. It was precisely of the same size, with a flat,
cemented floor, shelving sides, and circular, or rather _Aztec-arched_
roof. The passage was not straight, but wound about with frequent
turnings as far as we pursued it.

Why these curves were made, I never ascertained, although afterward I
gave the subject much attention. We started down the aqueduct at a brisk
pace, our candles being frequently extinguished by fresh drafts of air,
that struck us at almost every turn. Whenever they occurred, we paused a
moment, to reillume them, and then hastened on, as silently and swiftly
as before.

After traversing at least five or six miles of this passage,
occasionally passing arched chambers like that at the foot of the
staircase, we suddenly reached the termination of the aqueduct, which
was an apartment the _fac-simile_ of the one at the other end of it.
Here also we observed a stone stairway, and my companion at once began
the ascent. During our journey through the long arched way behind us, we
frequently passed through rents, made possibly by earthquakes, and more
than once were compelled to crawl through openings half filled with
rubbish, sand and stones. Nor was the road dry in all places. Indeed,
generally, the floor was wet, and twice we forded small brooks that ran
directly across the path. Behind us, and before, we could distinctly
hear the water dripping from the ceiling, and long before we reached the
end of the passage, our clothing had been completely saturated. It was,
therefore, with great and necessary caution, that I followed my guide up
the slippery stairs. Our ascent was not so tedious as our descent had
been, nor was the distance apparently more than half so great to the
surface. Pio paused a moment at the head of the stairway, extinguished
his candle, and then requested me by a gesture to do likewise. When this
was accomplished, he touched a spring and the trap-door flew open,
_upwards_. The next instant I found myself standing in a chamber but
dimly lighted from abov