By looking at any comprehensive map it can be readily seen that upon the western end of the Island of Cuba there is a cape known as San Antonio.

Opposite it and upon the eastern extremity of mystic Yucatan is Cape Catoche. Between these two points of land lies that body of water which connects the Gulf of Mexico with the Caribbean Sea and known as the Yucatan Channel.

Mr. Wilbur Wade, the distinguished arch?ologist, geologist, naturalist and scientist in general, had startled his associates of the World’s Geographical Society by a positive and unheard-of statement.

“I have made very careful soundings in the Yucatan Channel,” he said; “also I have compared the strata of the two capes, and it is my firm belief that at a period not so very remote there existed no channel between the two points of land. In fact——”

“Then you claim the existence of an isthmus between Cuba and Yucatan at some time?” interrupted Professor Brown.

“Just so,” agreed Mr. Wade.

“What has become of it, I would like to ask?”

There was just a bit of cynicism in this query. But then these two men had never been the warmest of friends. Wade bit his lip.

“What do you suppose has become of it?” he retorted. “Surely you don’t think it has taken wings and flown away?”

“But you were going to prove the matter to us,” returned Professor Brown, with a bit of sarcasm.

“If it is not an impossibility,” said Mr. Wade, ironically, “my opinion is that the isthmus is at present at the bottom of the Yucatan Channel.”

A number of the scientists moved in their seats. Professor Brown smiled broadly.

“A very simple matter to look at,” he said, pointedly. “Of course, it will be easy to furnish absolute evidence?”

Mr. Wade turned a cold stare upon the man who could speak so insultingly. Then he said:

2“Before I allow the fact to go upon record I shall prove it.”

“Then we shall have an isthmus between Labrador and Greenland; another ‘twixt Japan and Corea; still another between Sicily and the Italian Peninsula, and again——”

“One moment,” said Wade, politely. “You must remember that there is nothing improbable in any hypothesis you have named. If I am not able to prove myself right, you are not able to prove that the sunken isthmus never existed. I leave it in all fairness to our fellow-members.”

There was a slight murmur of approval, but there was yet incredulity.

“How do you expect to prove that there was once an isthmus between Cape San Antonio and Cape Catoche, may I ask, Mr. Wade?” spoke the chairman.

Mr. Wade drew himself up.

“By the only possible method,” he replied. “I shall visit it.”

The scientists all looked surprised. Professor Brown actually laughed out loud and slyly tapped his forehead. Finally the chairman said:

“Really, Mr. Wade, you must allow that that is quite a remarkable assertion. In what manner can you expect to visit this—this imaginary sunken isthmus?”

Wade’s eyes flashed.

“Imaginary if you will,” he said; “I shall conduct my investigations with a submarine boat.”

There was a great stir in the assemblage. Even Professor Brown forgot to interject his sarcasm.

“In a submarine boat?” repeated the chairman. “Does such a craft exist?”

“It does!” replied Mr. Wade, suavely. “And a very dear friend of mine is the inventor and owner.”

“His name?”

“Frank Reade, Jr., of Readestown.”

A murmur went through the throng. At once the sentiment began to change. Professor Brown faded from view.

Not one in that distinguished company but had heard of Frank Reade, Jr. His name changed the tide.

“Indeed!” exclaimed the chairman, with interest. “Is not Mr. Reade the inventor of an airship?”

“Yes, sir.”

“And of other wonderful things?”

“Exactly.”

“So he has built a submarine boat?”

“He has, and it is a success. He has kindly consented to assist me in locating the sunken isthmus. This boat is capable of remaining weeks under the sea. The plan cannot fail.”

In a moment dozens of the men were thronging about Wade, congratulating him heartily. Skeptical they were no longer. Foes a moment back, now they were fawning friends. Truly, nothing creates friendship like one’s success.

He was at once the lion of the hour. Scores of requests were showered upon him. Would he procure such a specimen? Would he solve such a marine problem? Was there any room on board the Sea Diver for another savant?

Et cetera, et cetera.

One still incredulous man ventured to ask:

“Will not the sunken isthmus be like all the rest of the bed of the sea? How will you prove it was ever above the surface?”

“If an isthmus did exist in that locality,” said Wade, logically, “there must have been habitations upon it. Probably I shall find ruins of a village, town or city, or remains of forests or craters, or river beds. There will be plenty of evidence if there ever was an isthmus.”

Wade went to New York from Washington on the night train. As he was whirled away upon the fast express he felt that he had really gained a great victory.

“I silenced that old hard-skull, Brown,” he muttered, with keen satisfaction. “And he deserved it.”

I know the reader will agree with Wade in this. That night he consumed in getting back to his Manhattan home.

The next day he packed his effects and started for Readestown.

Deep down in the heart of lovely hills upon a river navigable to the sea was the beautiful little city of Readestown.

A number of generations of Reades had lived there, and all had been inventors. But Frank Reade, Jr., the handsome young scion of the race, had proved the most famous of all.

The fact was, everything he took hold of succeeded.

It was bound to “go,” and with a snap and vim characteristic of the young American.

In undertaking the construction of a submarine boat Frank had hit upon that which had been an enigma to thousands of inventors.

But his marvelous ingenuity won the day and he triumphed.

The Sea Diver was conceived, outlined, charted and built. Then she was tested and proved an unqualified success.

In her outline the Sea Diver was long, slender and cylindrical, 3in the shape of her hull. This rested upon a deep keel to insure steadiness, which was a highly important matter.

The hull of the submarine boat was constructed of plates of steel, closely riveted. Above the cigar-shaped hull there was an open deck, extending from stem to stern.

In the center of the deck rose the dome, with the skylight and great observation window. Under this was the luxuriously-appointed cabin.

Just forward of this dome was the pilot-house, a smaller dome with heavy plate-glass windows. Here the steersman could direct the course of the boat and operate the electric keyboard which directed the vessel’s engines, for the motive power of the Sea Diver was electricity, furnished by a wonderful storage system.

Aft there arose a square structure with bull’s-eye windows, with a railed quarterdeck above it. This was called the after-cabin, and here were the staterooms and living quarters of the submarine travelers.

On this quarter deck there was a powerful searchlight, capable of a reach of fully two miles.

The interior of the Sea Diver lacked nothing in the way of equipment and appointment.

There were supplies of all kinds aboard for a cruise of two years.

Amidships and under the big dome were the wonderful electric engines, by means of which power was furnished for all the mechanism of the boat.

In the pilot-house was the electric keyboard. Here were the various little buttons and brass levers by means of which the doors and windows could be hermetically sealed, the huge tank filled with water instantly for the sinking of the boat, or again for raising it by the expulsion of the water with pneumatic pressure.

Thus the boat could be made to sink or rise at any desired depth; to go forward or back at the pressure of a button.

As wonderful as anything was the system of circulation by means of chemically-made oxygen. Under the pilot-house there was placed a generator which was capable of manufacturing pure oxygen, and also of extracting and destroying the bad air or gases as fast as they were created.

Little pipes and open valves extended to every part of the boat through which the oxygen was continually disseminated, so that the submarine boat might remain an indefinite time under water and the voyagers could be sure of breathing pure air all the time.

In fact, not a detail was lacking to make the Sea Diver a safe vessel, a comfortable home and a symmetrical, beautiful craft.

It was true that Frank Reade, Jr., had done his best to perfect the new submarine boat.

That he had been successful it was easy enough to see. Nobody had more confidence in him than his friend, Mr. Wilbur Wade.

The scientist was ready to embark upon a voyage to any part of the submarine world without considering for a moment the possible perils of such a thing. He was a firm believer in the practicability of submarine navigation, and the seaworthiness of the new boat.