.

"I wished to see you on an important business matter."

"Business? What business?"

"I will come to that presently, Porter. But it is important, very
important, I can assure you. I was going to ask you to call at a certain
place in Rockville and see me about it."

"What place?"

"A boarding-house at which I am stopping. It is a very nice place,
located on the river, and kept by a lady named Dunn--Mrs. Margaret
Dunn."

At once Dave remembered the letter picked up on Bush Island--the letter
written by Doctor Montgomery, and asking Jasniff to meet him at Dunn's
on the river. In that communication the doctor had said he would aid
Jasniff all he could, provided the Rockville student would assist him in
some transaction involving little risk--which would mean that there must
be something "shady" about it.

"Can't you explain the business to me without my going to Rockville?" he
asked.

"I cannot. I have some things at the boarding-house--some letters and
documents--I wish to show you. Day after to-morrow is Saturday. Can't
you come to Rockville in the afternoon and see me? I can assure you,
sir, it is very important, very important indeed!" And Doctor
Montgomery gave Dave a mysterious look.

"Do the letters and documents concern me personally?"

"They concern you, and--shall I tell you? Yes, I will! They concern you
and your sister. But don't ask me to say more now. I will explain all
when you come to see me."

Dave began to think rapidly. This fellow was friendly with Jasniff and
probably with Merwell also. Once Merwell had caused Laura Porter much
annoyance by holding certain letters she had written. Was it possible
Merwell still had some of her letters, and was he planning to make more
trouble because of them?

"I don't understand this business, Doctor Montgomery," he said, frankly.
"If it was so important why didn't you write to me, or telephone?"

"I will explain. This is important to you and your sister. It would hurt
your reputation to make anything public. I want to do things on the
quiet, see? Acting entirely in your interests, Porter. You will
understand it all when you call and--er--see the letters and documents,
and the photographs, especially the photographs."

"All right then--I'll come--if I can get off."

"About three o'clock in the afternoon?"

"Between three and four."

"Very good, sir, very good indeed. You will not regret coming, I can
assure you, sir. But one thing more. Let me c