It was not long before Phil came upon two pins sticking on a board of a closet. Then Roger ran into the next room and, after a short hunt, uncovered a flat pasteboard box with several more of the class pins, each a bit tarnished by the dampness, but otherwise uninjured.
"He must have come for the pins," said Ben. "That solves the mystery of how they disappeared from Mr. Dale's possession."
"Here is a postage stamp!" ejaculated Phil, and held it up. "It's an old German issue," he added. "And here are half a dozen others, all evidently torn from a sheet. Boys, Shadow must have taken the doctor's collection!"
Dave said nothing to this, for he had discovered a cupboard in a corner, tightly closed and with the wooden button of the door missing. He now opened the door of the cupboard with a knife.
"Hello, what's in there?" asked Roger, who was behind him.
"Seems to be some clothing," answered Dave, and hauled forth some loose garments and also an old satchel. The garments formed part of a sailor's garb, and the satchel was marked on the bottom with the name, "William Dill."
"It's Billy Dill's missing outfit!" cried Dave, eagerly. "Oh, Roger, how glad I am that I have found this! It's the best yet!"
All the boys were interested, for they knew Dave's story and the tale of the strange sailor. As Dave ran to the light with the satchel, they crowded around him.
"I think I am fully justified in opening this grip," said the country boy. He was so agitated he could scarcely speak.
"Why, certainly," cried Phil. "Open it, by all means. It may throw light on some things which Billy Dill has been unable to explain."