The Doctor stabbed a finger wildly in the direction of the coal cellar. "If you had seen what I have seen to-night, you would understand. You would be feeling exactly as I am now.""Hi! there goes one of them!--Halt!--Halt, you blue--" pop!--pop!--pop!The wind had been freshening since noon, and the rolling motion of the ship was not altogether agreeable to the inexperienced boys. They were about to have their first acquaintance with sea-sickness; and though they held on manfully and remained on deck through the afternoon, the ocean proved too much for them, and they had no appetite for dinner or supper. But their malady did not last long, and by the next morning they were as merry as ever, and laughed over the event. They asked the Doctor to explain the cause of their trouble, but he shook his head, and said the whole thing was a great puzzle.