“Then, if the sea invades us,” said Magdalen, “we must all run for refuge to you.”

Noel Vanstone saw his way to another compliment; and, at the same moment, the wary captain saw his way to another burst of science.

“I could almost wish the invasion might happen,” murmured one of the gentlemen, “to give me the happiness of offering the refuge.”

“I could almost swear the wind had shifted again!” exclaimed the other.  “Where is a man I can ask?  Oh, there he is.  Boatman!  How’s the wind now?  Nor’west and by west still—­hey?  And southeast and by south yesterday evening—­ha?  Is there anything more remarkable, Mrs. Lecount, than the variableness of the wind in this climate?” proceeded the captain, shifting the camp-stool to the scientific side of him.  “Is there any natural phenomenon more bewildering to the scientific inquirer?  You will tell me that the electric fluid which abounds in the air is the principal cause of this variableness.  You will remind me of the experiment of that illustrious philosopher who measured the velocity of a great storm by a flight of small feathers.  My dear madam, I grant all your propositions—­”

“I beg your pardon, sir,” said Mrs. Lecount; “you kindly attribute to me a knowledge that I don’t possess.  Propositions, I regret to say, are quite beyond me.”

“Don’t misunderstand me, ma’am,” continued the captain, politely unconscious of the interruption.  “My remarks apply to the temperate zone only.  Place me on the coasts beyond the tropics—­place me where the wind blows toward the shore in the day-time, and toward the sea by night—­and I instantly advance toward conclusive experiments.  For example, I know that the heat of the sun during the day rarefies the air over the land, and so causes the wind.  You challenge me to prove it.  I escort you down the kitchen stairs (with your kind permission); take my largest pie-dish out of the cook’s hands; I fill it with cold water.  Good! that dish of cold water represents the ocean.  I next provide myself with one of our most precious domestic conveniences, a hot-water plate; I fill it with hot water and I put it in the middle of the pie-dish.  Good again! the hot-water plate represents the land rarefying the air over it.  Bear that in mind, and give me a lighted candle.  I hold my lighted candle over the cold water, and blow it out.  The smoke immediately moves from the dish to the plate.  Before you have time to express your satisfaction, I light the candle once more, and reverse the whole proceeding.  I fill the pie-dish with hot-water, and the plate with cold; I blow the candle out again, and the smoke moves this time from the plate to the dish.  The smell is disagreeable—­but the experiment is conclusive.”

He shifted the camp-stool back again, and looked at Mrs. Lecount with his ingratiating smile.  “You don’t find me long-winded, ma’am—­do you?” he said, in his easy, cheerful way, just as the housekeeper was privately opening her e ars once more to the conversation on the other side of her.