On the morning of the next day, to my great surprise, I awoke completely restored. I thought a bath would be delightful after my long illness and sufferings. So, soon after rising, I went and plunged into the waters of this new Mediterranean. The bath was cool, fresh and invigorating.  
I came back to breakfast with an excellent appetite. Hans, our worthy guide, thoroughly understood how to cook such eatables as we were able to provide; he had both fire and water at discretion, so that he was enabled slightly to vary the weary monotony of our ordinary repast.
 
Our morning meal was like a capital English breakfast, with coffee by way of a windup. And never had this delicious beverage been so welcome and refreshing.
 
My uncle had sufficient regard for my state of health not to interrupt me in the enjoyment of the meal, but he was evidently delighted when I had finished.
 
"Now then," said he, "come with me. It is the height of the tide, and I am anxious to study its curious phenomena."
 
"What!"' I cried, rising in astonishment, "did you say the tide, Uncle?"
 
"Certainly I did."
 
"You do not mean to say," I replied, in a tone of respectful doubt, "that the influence of the sun and moon is felt here below."
 
"And pray why not? Are not all bodies influenced by the law of universal attraction? Why should this vast underground sea be exempt from the general law, the rule of the universe? Besides, there is nothing like that which is proved and demonstrated. Despite the great atmospheric pressure down here, you will notice that this inland sea rises and falls with as much regularity as the Atlantic itself."
 
As my uncle spoke, we reached the sandy shore, and saw and heard the waves breaking monotonously on the beach. They were evidently rising.
 
"This is truly the flood," I cried, looking at the water at my feet.
 
"Yes, my excellent nephew," replied my uncle, rubbing his hands with the gusto of a philosopher, "and you see by these several streaks of foam that the tide rises at least ten or twelve feet."
 
"It is indeed marvelous."
 
"By no means," he responded; "on the contrary, it is quite natural."
 
"It may appear so in your eyes, my dear uncle," was my reply, "but all the phenomena of the place appear to me to partake of the marvelous. It is almost impossible to believe that which I see. Who in his wildest dreams could have imagined that, beneath the crust of our earth, there could exist a real ocean, with ebbing and flowing tides, with its changes of winds, and even its storms! I for one should have laughed the suggestion to scorn."
 
"But, Harry, my boy, why not?" inquired my uncle, with a pitying smile; "is there any physical reason in opposition to it?"
 
"Well, if we give up the great theory of the central heat of the earth, I certainly can offer no reasons why anything should be looked upon as impossible."
 
"Then you will own," he added, "that the system of Sir Humphry Davy is wholly justified by what we have seen?"
 
"I allow that it is—and that point once granted, I certainly can see no reason for doubting the existence of seas and other wonders, even countries, in the interior of the globe."
 
"That is so—but of course these varied countries are uninhabited?"
 
"Well, I grant that it is more likely than not: still, I do not see why this sea should not have given shelter to some species of unknown fish."
 
"Hitherto we have not discovered any, and the probabilities are rather against our ever doing so," observed the Professor.
 
I was losing my skepticism in the presence of these wonders.
 
"Well, I am determined to solve the question. It is my intention to try my luck with my fishing line and hook."
 
"Certainly; make the experiment," said my uncle, pleased with my enthusiasm. "While we are about it, it will certainly be only proper to discover all the secrets of this extraordinary region."
 
"But, after all, where are we now?" I asked; "all this time I have quite forgotten to ask you a question, which, doubtless, your philosophical instruments have long since answered."
 
"Well," replied the Professor, "examining the situation from only one point of view, we are now distant three hundred and fifty leagues from Iceland."
 
"So much?" was my exclamation.
 
"I have gone over the matter several times, and am sure not to have made a mistake of five hundred yards," replied my uncle positively.
 
"And as to the direction—are we still going to the southeast?"
 
"Yes, with a western declination[2] of nineteen degrees, forty-two minutes, just as it is above. As for the inclination[3] I have discovered a very curious fact."
 
[2] The declination is the variation of the needle from the true meridian of a place.
 
[3] Inclination is the dip of the magnetic needle with a tendency to incline towards the earth.
 
"What may that be, Uncle? Your information interests me."
 
"Why, that the needle instead of dipping towards the pole as it does on earth, in the northern hemisphere, has an upward tendency."
 
"This proves," I cried, "that the great point of magnetic attraction lies somewhere between the surface of the earth and the spot we have succeeded in reaching."
 
"Exactly, my observant nephew," exclaimed my uncle, elated and delighted, "and it is quite probable that if we succeed in getting toward the polar regions—somewhere near the seventy-third degree of latitude, where Sir James Ross discovered the magnetic pole, we shall behold the needle point directly upward. We have therefore discovered by analogy, that this great centre of attraction is not situated at a very great depth."
 
"Well," said I, rather surprised, "this discovery will astonish experimental philosophers. It was never suspected."
 
"Science, great, mighty and in the end unerring," replied my uncle dogmatically, "science ha............