Washington heard the boy as he turned the faucet to draw the liquid, and spoke to him, as the colored man was rather lonesome at his post.  Mark did not linger more than a minute or two, but when he returned to where he had left the food he was much surprised.

There was not a trace of it to be seen.  The dishes were on the table, but every vestige of bread and meat had disappeared.

“I wonder if a cat or dog has been here,” was Mark’s first thought.  Then he remembered that no such animals were aboard the Mermaid.

Something on the floor caught his eye.  He stooped and picked it up.  It was a slice of bread, but in such shape that the boy stared at it, puzzled as to how it could have become so.

It was flattened out quite thin, but the strangest part of it was that it bore what seemed to be the marks of thumb and fingers from a very large hand.  So big, in fact, was the print, that Mark’s hand scarce covered half of it, and, where the bread had been squeezed into a putty like mass (for it was quite fresh) the peculiar markings on the skin of the tips of the fingers were visible.

“It looks as if a giant grabbed this slice of bread,” Mark observed.  “There are strange happenings aboard this ship.  I wish I knew what they meant.”

He looked all around for the food, thinking perhaps a rat had dragged it off, but there was no trace of it.

Suddenly the boy thought he heard a sound from the big storeroom.  He was almost sure he heard something moving in there.  He started toward the door when he was stopped by hearing the professor’s voice call: 

“Don’t open that door, Mark.  Have I not told you that place must not be entered?”

“I thought I heard some one in there,” Mark replied.

“There is nothing in there but some apparatus of mine,” Mr. Henderson said.  “I want no one to see it.  What is the matter?”

Mark explained matters to the scientist, who had, as he said later, arisen on hearing the boy, moving about.

“Oh, it was a rat that took your stuff,” Mr. Henderson said.  “I guess there are some pretty big ones on the ship.  Get some more food and go to sleep.”

Mark felt it best to obey, though he was by no means satisfied with the professor’s explanation.  He listened intently to see if any more noises came from the storeroom, but none did, and he went to bed.

Several times after that Mark tried the experiment of leaving food about.  On each occasion it was taken.

“It looks as if the ship was haunted,” he said.  “Of course I know it isn’t, but it’s very queer.  They must be strange rats that can get food from shelves when there is only the smooth side of the ship to climb up,” for on some occasions Mark had tried the experiment of putting the food as nearly out of reach as possible.

It took several nights to learn all this, and, as he did not want to take any one into his confidence, he had to work in secret.  But, with all his efforts he learned nothing, save that there was something odd about the ship that he could not fathom.