"There he is now, digging again," said Bob, quickly, "and he's on our beach, too. I guess now we've got a right to ask him what he's after."
Rather bashfully the boys approached the old man. He paid no attention to them, but went on digging. Suddenly he was observed to throw aside his shovel, make a grab for something in the sand, and then he cried out:
"I have it! I have it! At last I have found it!"
Eagerly the boys rushed forward. The man did not seem to notice them, but was closely looking at something in his hand.
"Have you found the pirate gold?" asked Bob, boldly.
The man looked at the boys. He did not seem annoyed now.
"Gold! No, I wasn't looking for gold," he said. "But I have found a very rare kind of seashell for which I have been searching all Summer. At last my scientific collection is complete. My search is ended!"
The boys did not know what to think.
"Weren't you looking for gold?" asked Sammy, much amazed.
"Gold! No, I care nothing for gold. I am a college professor and from my studies I decided that a certain rare seashell was to be found on this coast. I came here, and dug in many places for it. I even dug at night, for the creature that lives in this shell is said to prefer to feed at night. But I never had any luck until now."
"Then you know nothing about pirates," said Sammy, sadly.
The professor looked curiously at them.
"Ah, I have seen you boys before," he said, musingly.
"Yes, we followed you once," said Frank.
"I remember now. And I drove you away. I did not mean to be impolite, but this shell is a very delicate one, and you were walking over the land where I thought I might find
