er listening intently for a few moments he
scrambled in; and after again listening he produced a bull's-eye lamp--a
most unusual thing for a native to possess--and carefully lit it.

He next examined a revolver and a knife he carried in a girdle under a
loose garment he had wrapped round him, and in addition to these weapons
he had an iron rod about three feet and a-half long, similar to what
many Fakirs carry.

He now advanced along a narrow passage which widened into a large cave,
from which opened another narrow passage, and this he proceeded
cautiously to explore, but when he had gone about a hundred yards it
came to an abrupt end, the roof here being exceedingly high, and as he
flashed his light around he could not see the top.

For the space of an hour he probed about with his iron rod, and felt in
the cracks and crevices in the walls; then suddenly he sat down, and,
had any one been near enough, they would have heard him chuckling to
himself, for he had made a great discovery.

In a short time he made his way out of the cave and disappeared into the
darkness of the night.

"What do you make of this, Ellison?" said the Doctor early next morning.
"I have just found this note in my tent; it is written in Punjabi, and
in English it reads: 'If the Sahib wishes to learn where his son is he
will be told if you promise to give up the other pieces of stone you
found. Let the Sahib write his promise on the blank part of this paper
and place it on the small olive-tree near the salt spring. The Sahib's
men need not watch, for they will not see who fetches it.'

"Do you think it is a hoax?" asked the Doctor.

"I don't know. I scarcely think so. I wish Burton was back," said Tom,
who thought that Burton's experience might enable him to get something
of a clue from the strange message. "They have got all the stones," he
added.

"We took others that did not belong to the slab," said the Doctor.

"Of course, I had forgotten; and the writer of this is under the
impression they are parts of the slab," remarked Tom.

"If this is genuine, then Mark is a prisoner, which is Burton's opinion;
and I believe he is acting in some secret manner on his opinion," said
the Doctor.

After a long consultation the Doctor tore off the blank piece of paper
and wrote on it in the native language: "You must first give me some
proof that you know where my son is before I promise to comply with your
request. Let him write to me."

"We