“Kin I carry th’ box for you, boss?” he asked, at the same time reaching for it.

The doctor’s thin figure seemed fairly to shrink at the idea.

“No, no!” he cried.  “It iss not for you to carry!”

He hastened up the gangplank, clutching the chest close.  At the top Captain Selover met him.

“Hello, doctor,” he squeaked.  “Here in good time.  We’re busy, you see.  Let me carry your chest for you.”

“No, no!” Dr. Schermerhorn fairly glared.

“It’s almighty heavy,” insisted the captain.  “Let me give you a hand.”

“You must not touch!” emphatically ordered the scientist.  “Where iss the cabin?”

He disappeared down the companionway clasping his precious load.  The young man remained on deck to superintend the stowing of the scientific goods and the personal baggage.

All this time I had been thinking busily.  I remembered distinctly one other instance when Dr. Schermerhorn had disappeared.  He came back inscrutably, but within a week his results on aerial photography were public property.  I told myself that in the present instance his lavish use of money, the elaborate nature of his preparations, the evident secrecy of the expedition as evidenced by the fact that he had negotiated for the vessel only the day before setting sail, the importance of personal supervision as proved by the fact that he—­notoriously impractical in practical matters, and notoriously disliking anything to do with business—­had conducted the affair himself instead of delegating it,—­why; gentlemen, don’t you see that all this was more than enough to wake me up, body and soul?  Suddenly I came to a definite resolution.  Captain Selover had descended to the pier.  I approached him.

“You need a mate,” said I.

He looked me over.

“Perhaps,” he admitted.  “Where’s your man?”

“Right here,” said I.

His eyes widened a little.  Otherwise he showed no sign of surprise.  I cursed my clothes.

Fortunately I had my master’s certificate with me—­I’d passed fresh-water on the Great Lakes—­I always carry that sort of document on the chance that it may come handy.  It chanced to have a couple of naval endorsements, results of the late war.

“Look here,” I said before I gave it to him.  “You don’t believe in me.  My clothes are too good.  That’s all right.  They’re all I have that are good.  I’m broke.  I came down here wondering whether I’d better throw myself in the drink.”

“You look like a dude,” he squeaked.  “Where did you ever ship?”

I handed him my certificate.  The endorsements from Admiral Keays and Captain Arnold impressed him.  He stared at me again, and a gleam of cunning crept into his eyes.

“Nothing crooked about this?” he breathed softly.

I had the key to this side of his character.  You remember I had overheard the night before his statement of his moral scruples.  I said nothing, but looked knowing.