"No, sir," replied Rollo; "but how did you know that my name was Rollo?"
"O, I heard about you down in the cabin," replied the stranger; "and about you too, Jennie, and your beautiful little kitten. But I will explain the meaning of the bells to you. I know all about them. I belong on board this ship. I am the surgeon."
"Are you?" said Rollo. "I did not know that there was any surgeon in the ship."
"Yes," replied the gentleman. "It is quite necessary to have a surgeon. Sometimes the seamen get hurt, and require attendance; and then sometimes there are cases of sickness among the passengers. I have got quite a little apothecary's shop in my state room. I will show it to you by and by. But now about the bells.
"You must know," continued the surgeon, "that people strike the time at sea in a very different manner from that which is customary on land. In the first place, they have a man to strike it; they cannot have a clock."
"I do not see why not," said Rollo.
"Because at sea," rejoined the surgeon, "the time changes every day, and no clock going regularly can keep it. Time depends upon the sun, and when the ship is going east she goes to meet the sun; and it becomes noon, that is, midday, earlier. When the ship is going west, she goes away from the sun, and then it becomes noon later. Thus noon has to be fixed every day anew, and a clock going regularly all the time would be continually getting wrong. Then, besides the rolling and pitching of the ship would derange the motion of the weights and pendulum of the clock. In fact, I don't believe that a clock could be made to go at all—unless, indeed, it were hung on gimbals."
"What are gimbals?" asked Rollo.
"They are a pair of rings," replied the surgeon, "one within the other, and each mounted on pivots in such a manner that any thing hung within the inner ring will swing any way freely. The lamps down in the cabin are hung on gimbals."
"Yes," said Rollo, "I saw them."