the highest wall of
the ancient ruins, well screened from the ardent rays of the tropic sun,
which had not yet risen sufficiently high to interfere with their
comfort, and for about the third time the boys were giving their account
of the previous evening's adventure, with nothing more visible to show
than a few scratches from the stones and the traces of pricks from the
many thorns, when the doctor said, as if he were delivering a lecture,
and frowning severely the while, "Care, care, care. If ever our eyes
should be called upon to carefully discriminate where we are going,
there never can be such need for discrimination as here."

"You are right, doctor," said Sir James. "You must be careful, boys;
eh, doctor?"

"Yes," said the latter. "You see, we have done nothing yet to clear
away the tangle of growth that covers the stones and the remains of old
buildings. I fully believe that this place is honey-combed with
passages and cell-like remains, and that there may be dozens of old
wells and other reservoirs of water. There is the little river yonder,
of course, but if, as I fully believe, this place for miles round was
all roughly and strongly fortified, it seems quite probable that the
inhabitants, who were gold-seekers, were in the course of generations
besieged by the many enemies who coveted their wealth and resented the
coming of strangers to settle in their land. If this were the case, in
this heated district water would have been most valuable, and the
approaches to the river were doubtless guarded by the enemy. Thinking
of all this, one sees good reason for the existence of such a well-like
place as you encountered yesterday."

"Yes," said Sir James, "and I quite agree with you, doctor, that if we
could find them where they are buried by the old buildings that have
crumbled in, and overgrown by bushes and creepers, there are scores of
such places."

"Well," said the doctor, "one would be sufficient for our supply of
water, but we must, if possible, find out as many as we can for our own
safety."

"So as not to fall down any of them?" said Mark. "Dean and I don't want
another such adventure as we had last night."

"No," said his father; "it might be very serious. Let it be a lesson to
you, boys."

"It was, father," said Mark, and he gave his cousin a meaning look,
which was returned, the latter saying to himself, "It takes some of the
conceit out of you, old fellow."

The conversation then tu