"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 both know where the salt spring is, Tom, so I will take the paper there, and you go to some place where you can watch the spring through your field-glasses," said the Doctor.
"Very good. By the time we get a reply Burton may be back," said Tom, and they left the camp.