After supper, and when settled back once again in the cushions of their sleeper, Cobb immediately resumed the conversation about the pneumatic roads.

“They must be very rich and powerful corporations, these which own such lines as this?”

“No,” returned Rawolle; “for they are not owned by individuals, but by the government. All railroads in the United States are in the hands of the government, and are operated with a view to just covering expenses.”

“Are the rates of passage high?”

“We do not consider them so. There is one fixed rate throughout the country of one cent per mile.”

“But,” musingly inquired Cobb, “is not there a difference in operating the roads? Are not some more expensive to the government than others?”

“Certainly,” answered Rawolle. “But, like postage on letters, a universal rate is found to be the best; the larger and more patronized roads paying the losses incurred by the smaller and country routes.”

“I presume,” said Cobb, “that there can be but few changes in the general management, supervision, etc., of the roads from those in vogue in my time?”

“There you make a mistake,” quickly returned the other; “for, having been connected with the pneumatic lines, I am well posted in what is done to-day and what was the manner of operating railroads during the first part of the twentieth century. Nearly every detail of to-day’s management differs from that in vogue a hundred years ago. It would tire you for me to go into details. A few facts, though, I will give you: All freight is of two classes, and is sent at so much per pound per mile. At the sending point it is stamped similarly to a letter, showing date, place of shipment, destination, etc. The same rule is followed in regard to baggage of individuals, the owner having a duplicate of the stamp placed upon his baggage. There are no tickets shown or taken up on the pneumatic lines, but the names of passengers to depart from the train at intermediate points are telegraphed ahead, and the persons are looked after by the inspectors. On all lines the tracks are double, trains passing but one way on each line of rail. There are no whistles or bells to the locomotives of the service lines; no tender with its coal and water; no cab in the rear for the engineer; no furnace and fireman. The locomotive is an electric one, with the engineer in a cab in front. In place of the huge boilers is an iron and steel tank containing the storage batteries. The whole weight is nearer the rail, thus bringing down the center of gravity and reducing the danger from oscillation.”

As Rawolle was thus enlightening Cobb about the innovations made in the last century, the sleeper door opened, and a trainman entered and walked direct to their section and asked for Mr. Rawolle, saying he had a telegram for him, at the same time handing out the envelope.

Rawolle took it and thanked the man, who then left the car.

“He hit the right man squarely that time!” surprisedly exclaimed Cobb. “They seem to know you here.”

“Not at all,” replied Rawolle, smiling, while he tore open the envelope. “Every person on the train is known by name, and section, and car. Such is the system.”

He opened and read the telegram.

“There!” he exclaimed, after a moment, extending the telegram to Cobb. “There is an order from the Secretary of State to stop at the Central Sea.” And he and Lyman looked quizzingly at their companion, as he slowly took the telegram and read:

Cobb read it through twice ere he ventured any remark; then, handing it back while a troubled look overspread his countenance, he said:

“Cairo is in Illinois, at the junction of the Ohio with the Mississippi; but I fail to comprehend the import of the words ‘Central Sea.’ The submarine boat spoken of does not surprise me, for I would naturally expect that that which was almost an accomplished fact in 1887, would be an actual success at this late date.”

“There is no Ohio River, or not as was in your time. The Ohio is now but a small stream flowing into the Central Sea,” replied Rawolle.

“Again those words ‘Central Sea;’ what does it mean? Is there an inland sea?” and Cobb looked inquiringly at both of the others.

“There is,” slowly spoke Rawolle.

“And a mighty big one, too,” put in Lyman.

Cobb was highly educated and of a sanguine temperament; he neither doubted what seemed impossible, nor did he believe until the facts were clearly before his mind. He was perfectly cognizant of the physical geography of the United States, and did not understand under what conditions a great inland sea could have been formed, or maintained.

Settling himself back in his seat and breaking the circuit of the electric light to lessen the glare in their faces, Rawolle continued:

“I will give you some facts concerning this sea, for, now that you are one of a new generation, you have much to learn, and we cannot pass the hours between now and bed-time to better advantage. On the last day of August, 1916,” he began, “at about 14 dial, or as they then said, 2 P.M., that which was taken, at the time, as the shock of a great earthquake, was felt by thousands of persons throughout the central portion of the United States. In less than two hours later, the nation was informed of the true nature of the shocks which followed each other in rapid succession. It was the explosion of natural gases deep down in the strata of the earth’s crust, and the scene of the disturbances covered a vast area of territory. During the following week the shaking and trembling of the earth caused great destruction in many cities and towns not otherwise affected. Houses fell, the water supply failed, and other serious results were experienced. But throughout portions of the area now covered by the Central Sea, the scene was terrible, awe-inspiring, horrible. The earth heaved and sank; huge cracks opened, and flames hundreds of feet high shot into the air; thunder and lightning added to the horrors of the situation. The bursting of the earth’s crust was attended by an appalling roar and crash, as if a million peals of thunder had combined in one grand effort to terrify mankind; then came a pall of dense, black smoke that wrapped the land in darkness. Consternation seized upon the people, and well it might, for when the full import of the disturbances was known, it was only then ascertained that a great cataclysm had befallen the nation. Without going too much into details, for you can later on gain a full knowledge of this great physical disturbance from the books published soon after its occurrence, I will explain but a few of the facts causing it. You are aware, Mr. Cobb, to what extent natural gas was used in the United States in 1887; that there were thousands of wells pouring out millions of cubic feet daily; that many of them showed pressure of from ten to twenty atmospheres. From the time you left the world, as it were, until August, 1916, gas wells were being sunk all over the country drained by the Ohio and its tributaries. Their number was way up in the thousands. Billions of cubic feet of natural gas were being consumed or flowing to waste daily. Pittsburgh alone used 300,000,000 cubic feet a day in its vast manufactories. The earth in the Ohio basin was honey-combed with the gas pockets and strata, and gas veins were struck in which the gas was under such pressure that the flow could not be checked by human hands. It was 14 dial, as I have said, on the last day of August, 1916, and the workmen in the large foundry of Dillenback & Co., at Lakeside, on the Ohio, some fifty miles below Pittsburgh, were tapping a huge melting of aluminum bronze for the purpose of casting the outer shell of one of the latest model guns of that period. But let me first describe the interior arrangements of the foundry, that you may fully grasp the situation as it then stood, and the cause of the results which followed. Natural gas was, and had been for a long time, the fuel used in these works. Up to 1914 the gas boring of Lakeside had furnished all the gas required. This well was of ten-inch bore, and reached a depth of 4,737 feet, but in the year mentioned the well had failed to furnish gas at any pressure. The standard pipe had been moved and an iron plate set over the mouth of the tube, on a level with the floor. Five hundred feet from this well a boring to 4,016 feet had struck a new stratum, giving vast quantities of gas at a pressure of five atmospheres. To revert back: Just as the tapping of the furnaces was made, the steam boiler of the crane engine, through some unaccountable cause, burst. The concussion shook the buildings, tore up the ground, displaced the iron plate over the disused gas well, and broke the aluminum furnaces, letting over one hundred tons of molten metal flow rapidly across the foundry floor. Recovering from the first shock and fright of the explosion, all efforts were at once made to arrest the flow of the liquid stream, or to divert its course away from the old well. That well, as all knew, still contained gas intermingled with common air, the mixture being of a very explosive nature. All perceived at a glance what would be the consequences if such a mass of molten metal should precipitate itself into the old well and fall over 4,500 feet into the interior of the earth’s crust; the shock at bottom, the continuance of heat, the explosive medium through which it would pass, all were dangers to be dreaded. The gas strata were overlaid and underlaid by water and air strata; the breaking of one into another would cause a commingling of their constituent parts, and form explosive compounds of the most dangerous types. Human efforts failed to stem the fiery stream in its onward course across the foundry floor. With a bounding, hissing, and, as it were, victorious cry, the river of melted aluminum approached, reached and went plunging down into the old supply-pipe. Who could describe the terrible effect! Of all those hundreds of human beings employed in Dillenback’s works, but two lived to tell the story of the catastrophe. These two men knew only one thing: that the earth seemed to shake to its very center, and they were hurled down among the debris of the fallen buildings, while sheets of fire almost scorched their very souls. Peal upon peal of thunder reverberated about them, and then darkness buried everything from their vision. Burned, bleeding, and nearly dead, these two men found themselves pinned down by the timbers of the works. Fire was upon every side; the timbers were burning, the heat was oppressive, and from a horrible death no man could save them. There was a higher Power, though, who had ordained that these two men should be witnesses of the full effects of this mighty effort of nature to overcome the grasping endeavors of man to accumulate wealth at the expense of reason. A sudden rush of waters from beneath them cooled their parching bodies, extinguished the fires about them, raised the mass of timbers which pinned them down, and gave them their liberty. You can read of this escape, as it is fully chronicled. This was the cause; now the effects. Are you tired?” seeing Cobb so quiet; “or would you like a drink of something to warm the inner man?”

Cobb had sat with scarcely a movement, save the heaving of his chest, as he listened to this terrible narrative. The last words of Rawolle seemed to awaken him.

“No, and yes,” he slowly replied. “Let us take a glass of wine and retire. I wish to think this over before you finish. My head aches, and I need rest.”

A few minutes later, all was quiet in the first sleeper of the Central Pneumatic No. 3, east.

It was 2:25 dial, or 25 minutes past 2, the next morning, when the Central Pneumatic arrived at Cairo.

Here Rawolle’s party was met at the train by an officer from the government submarine boat Tracer, and conducted aboard that vessel, which lay at anchor in the stream. Cobb was informed that, as it was so early, he had better retire and take a little more rest, for they would not weigh anchor until 7 dial. Acquiescing, he was shown to his state-room.

It was a cozy affair, indeed, that Cobb was ushered into—a little, but handsomely furnished room, containing all that one could desire in a thoroughly well-appointed apartment. Electric lamps threw a charming, subdued light over everything in the room, while an electric heater diffused a gentle warmth which was most agreeable this September morning. Retiring to rest, Cobb dreamed of nothing but pneumatic railways, submarine boats, and gigantic convulsions of nature.

It was about 7 dial when both Rawolle and Lyman came and awoke their guest, who, after a refreshing bath and a delicious breakfast, ascended to the upper deck of the Tracer.

The main deck of the vessel was of very small area amidship, some two feet above the water-line, and inclosed by an iron railing.

A beautiful scene presented itself to his view. The Tracer lay about half a mile from the docks of Cairo, and that city was just awakening to its daily round of bustle and activity. The stream was covered with shipping, some at anchor, while others were plying between the city and the opposite shore, a mile and a half away. Sailing craft there were a plenty, but no steamers, though there were many vessels moving swiftly through the water, yet showing no smoke or funnels.

This fact was immediately noted by Cobb, and inquiry made of Lyman, who stood near him, as to why there was no smoke visible.

“Neither coal nor wood is now used for marine propulsion,” replied Lyman. “Lipthalite vapor, or lipthalene, is now the motive power of vessels without sails. I will show you some of this lipthalite, later on, in this vessel.”

Turning his eyes from the busy and charming scene about him, Cobb’s thoughts came back to his immediate surroundings. What was he standing upon? The small, water-flush deck of a metal submarine vessel, the total area of which could not exceed a thousand square feet. A number of peculiar openings, valves, and pipes abutted on the deck, and a single metal mast stood at the bows; but no smoke-stack or other accessories to propulsion were visible.

Surveying all these things, he was about to ask information concerning their use, when Lieutenant Sibley, the officer in command, made his appearance, and was introduced to him.

“I am sorry I was not aboard to welcome your arrival, last evening, Mr. Cobb,” he began, in a courteous and pleasing tone of voice, “but I was detained in Central City, across the river, until early this morning. I hope you slept well, and are ready for the trip to Pittsburgh?”

“Not only ready, but anxious for it,” was the reply.

In a few moments more, by order of the Lieutenant, the anchor was raised, and the Tracer moved up the stream, headed E. ¼ N.

As the vessel moved through the shipping, the national colors, which were displayed from its mast, were saluted by the dipping of flags and sounding of whistles.

A hoarse-toned marine whistle, almost at Cobb’s feet, answered these salutations, and also caused that gentleman to jump back with a startled expression.

Drawing his hand from the whistle button, Lieutenant Sibley apologized for frightening him, saying:

“It did not occur to me that I had others aboard than those who are accustomed to these vessels.”

The Tracer was a cigar-shaped vessel of two hundred feet in length by twenty beam, or middle diameter, and of nearly 1,000 tons displacement when submerged.

With an outer shell of aluminum bronze and an inner shell of the finest steel, the vessel combined great strength with a minimum amount of metal in its construction.

“Gentlemen, if you will follow me,” said Lieutenant Sibley, “I will show you over the vessel.”

Descending the companion-way, the entrance to which could be closed by an air-tight door, the party proceeded about the vessel.

Longitudinally and horizontally, from apex to apex of the cones, was a steel deck dividing the vessel into two equal parts. The first forty-five feet of each cone contained the tubes of compressed air and oxygen. There were in each end about 2,500 feet of five-inch steel tubes, one-half inch thick, containing over 4,500 cubic feet of air under a pressure of 1,500 pounds per square inch. This was sufficient, as Lieutenant Sibley explained, to sustain active life for the entire crew for two hours. “But we have other facilities,” continued the Lieutenant, “by which the vitiated air is deprived of its carbonic acid, and then recharged with the lipthalene gas from the receivers and oxygen from the pipes, giving about eight hours of active life to the inmates of the vessel when totally deprived of air externally.”

The store-rooms, mess-rooms, and quarters of the men were visited. Small though these rooms were, they were made with every convenience, and given every useful contrivance which this great age of invention could produce.

The Tracer was not a war vessel, but belonged to the Geographical Bureau, and was used in charting the Central Sea. Her complement was small: two engineers, two pilots, one electrician, cook, assistant cook, captain’s boy, two helpers, and two officers. Everything was so admirably arranged, and machinery played such a wonderful part in the power required to handle the vessel, that a larger force was not only unnecessary, but would have been detrimental to a satisfactory working of the vessel.

Cobb called attention to the steel partitions between the rooms, and asked why so much strength was required.

“There are,” answered Lieutenant Sibley, “twelve partitions, dividing the vessel into twenty-six compartments. In case of accident to the outer shell, whereby water might gain ingress, that particular compartment can instantly be closed and the flow of water confined to it. Before going down into the engine-room, I will give you some idea of this remarkable vessel. The Tracer, when fully submerged, displaces 1,000 tons of water. The shell of the vessel is of 1½-inch steel, covered externally by an aluminum armor of .3 of an inch in thickness, and weighs 570,000 pounds. The steel deck upon which we stand weighs 500,000; the steel partitions, braces, and iron-work weigh 195,000; the engines and machinery, 200,000; compressed air pipes, 125,000; the water cylinders, which you will soon see, weigh 100,000; all other parts, stores, lipthalite, etc., are allowed 50,000 pounds. Now, added to all this, is an immense aluminum-covered iron weight of 150,000 pounds attached to the bottom of the vessel, and which can instantly be freed and dropped from the ship into the sea, by simply breaking an electrical connection. This circuit is accessible from all parts of the vessel. Let us descend into the engine-rooms, and I will there explain why I have been so particular in giving you these weights.”

Following the Lieutenant down the narrow ladder into the depth below, Cobb, Rawolle, and Lyman were soon facing the powerful but small engines of the Tracer.

The room was large, clean, warm, and brightly illuminated by electricity. Here, Mr. Lochridge, the first engineer, was introduced by Lieutenant Sibley.

Cobb had seen the engines of many of the first-class vessels of his day, had noted their power and huge dimensions; but never before had he perceived such beautiful specimens of strength combined with size; nor did the finest workmanship he had ever seen approach to the perfection of the engines he saw beating and pulsating before him.

Cobb looked them carefully over before venturing any remark. He noted an absence of steam and heat, the peculiar construction of the boilers, and many other, to him, new inventions.

“I believe, Mr. Rawolle,” he finally said, turning to him, “that you informed me last evening that no steam was used at the present day, but in its place, lipthalite?”

“That is our fuel and vapor nowadays,” broke in Mr. Lochridge.

He led the way to two receivers, bearing some slight resemblance to the boilers of a steamer.

“Here are our boilers and furnaces combined,” he continued; “and these,” as he laid his hand upon two very peculiarly constructed frontal additions, which had quite a number of straight pipes running into the large receiver, “are our furnaces, if you choose to call them by such a designation; we call them generators. Lipthalite is our fuel and gas developer.”

Mr. Lochridge stooped down and took from a case, containing many more, a stick of dark-brown material about four feet long by one inch in diameter, and handed it to Cobb for his inspection, saying:

“That is lipthalite. These rods are placed in those tubes, and, by proper mechanism, pushed through into the field of an arc light situated in the generator. Gas is evolved in great quantities, but the composition burns only while in the field of the arc. Little heat is developed. The gas is delivered to the cylinders in the same manner as was steam in your day.”

“What is the volume of gas as compared with the solid base? and is it cheaper and as efficient as vapor of water?”

“I expected that question, Mr. Cobb,” returned Mr. Lochridge, “and will explain it. One cubic foot of water, as you know, produces nearly 1,700 cubic feet of steam; one cubic inch of gunpowder makes about 1,500 cubic inches of carbonic acid and nitrogen gases; while one cubic inch of lipthalite will evolve 500 cubic feet of lipthalene, a combination of nitrogen, carbonic acid, and other gases. The ratio between water and lipthalite, evolved into gas, is as 1 to 500. In other words, to operate the engines of this vessel at a given speed for one hour, requires, of coal and water, one and thirty-one tons respectively; while of lipthalite, twenty-three pounds. Leaving out the question of water, of which there is a plentiful supply surrounding the vessel, the gain in a twenty-four hours’ run for lipthalite over coal is as 1 is to 96; or one ton of lipthalite is used where ninety-six tons of coal would have been required.”

“It is a wonderful discovery!” exclaimed Cobb, and a far-away, dreamy expression came into his eyes. For an instant his mind went back to the days, long years ago, when he had spent hours in his laboratory, at the Presidio, searching for this very same agent—the storage of great power in small volume—and his partial success in the discovery of meteorite. Then his thoughts led him to the remembrance that his new explosive had been sent to Washington. What had become of it? Lost, lost, years ago!

“Do you comprehend the advance in science that has been made in a hundred years?” and Rawolle broke his reverie by gently touching him on the arm.

“Can I help it? Could anyone have dreamed of such a power as this?”

Yes. He had dreamed of it; and many, many times. But too modest to venture the knowledge that his thoughts and work had been centered on such a grand invention, he turned to Mr. Lochridge, and abruptly asked:

“Is lipthalite turned into gas by explosion?”

“By no means,” quickly returned that gentleman; “by inflammation, and inflammation alone, and not very fast, either. In our generators, here, it is at the rate of about two hundred and fifty feet of these sticks per hour.”

“Strange that I should have worked on this very principle!” he said, half aloud; then turning to Lieutenant Sibley, he exclaimed:

“You spoke of water cylinders; where are they?”

“Under the grating, Mr. Cobb.”

Mr. Lochridge raised the grated flooring, and showed three iron cylinders, each divided into halves, with piston-rods and cylinder-heads. They were about four feet in diameter by twenty-three feet long.

“These, gentlemen,” he continued, “are connected by pipes with the outside of the vessel. Water can be admitted into any one or all of these cylinders, and, in two minutes, driven out by the pistons. Should these pistons fail, from any cause, to work, pumps connected with the cylinders could perform the same duty in ten minutes. I gave you the weights a few minutes ago; what did I make them?” taking a piece of paper and pencil from his pocket, and making a few notes. “Yes; 1,940,000 pounds, or just thirty tons less than our displacement. The water cylinders have a capacity of fifty tons. By allowing thirty tons of water to enter the cylinders, our weight is equal to our displacement, and we sink. Allowing all loss of weight aboard ship during a cruise, and which never exceeds twenty tons, we can always decrease our buoyancy and sink to the bottom, if necessary. Now, here,” pointing to the left, and along the walls of the vessel, “are the dynamos for the electric lights, fans for circulating the fresh air, steering apparatus, electric heaters, exhaust pumps for expelling the vitiated air and drawing in the fresh, and many other inventions, the uses of which you can learn at your leisure.”

The engine-room of the Tracer was indeed a curiosity-shop to Junius Cobb. Pipes in every direction; electric wires crossed and recrossed one another; peculiar machines occupied each side of the room, and a hundred other things, strange to him, were upon either side. Leaving the engine-room, Lieutenant Sibley led the way to the instrument-room of the ship. Here a new treat awaited Cobb.

Situated just at the junction of the main shell and the forward cone, was the pilot’s, or instrument, room. In an easy-chair, in front of a box about two feet square, and resting on the table, sat Mr. Irwin, the first pilot of the Tracer. On either side of him, and fastened to the walls of the room, were a great number of delicate instruments, some of which were familiar to Cobb. At either side of the box on the table were several rows of push-buttons; to the left, a fine compass, and to the right, speaking tubes and bells.

“You met Mr. Cobb at breakfast, did you not, Irwin?” questioned Lieutenant Sibley, as the pilot arose and greeted the entrance of the party with a smile.

“Yes, I had that pleasure,” he returned, bowing. “Have you been over the ship?” to Cobb.

“We have taken it all in, Mr. Irwin,” said Lyman, answering for the party.

“How is the course? and where are we now?” asked the Lieutenant.

“It is now 9:35, and we are headed northeast by east. Cairo is to our rear ninety-five miles. We are over Princeton, thirty miles north of Evansville,” was the reply.

“You may make Louisville. What time will we get there?”

Consulting his chart a moment, Mr. Irwin replied:

“Louisville is on our course now, and distant one hundred and eighty-eight miles. We will make it at 14:12.”

“Now, Irwin, I wish you would explain the mysteries of your castle to Mr. Cobb, and then bring the gentleman to my cabin. You will excuse us a few minutes, will you not, Mr. Cobb? I have some official papers for Mr. Rawolle’s inspection. Mr. Lyman, will you come along, too?” to that gentleman.

As they left the room, Mr. Irwin turned to Cobb, and held a few minutes’ conversation regarding the remarkable experience of the latter; then, rising, he pointed to the right wall and said:

“These are instruments used aboard submarine vessels of to-day. There is a thermometer for interior temperature, that for exterior temperature; here are electric dials giving the humidity in various parts of the ship. These dials to the left show the motion of the fans, dynamos, and all other moving machinery aboard. The interior pressure is here noted,” placing his hand upon a barometer, “and the exterior, there. The purity of the air is indicated by this little delicate meter. The speed of the vessel is shown on that reel, which is connected, electrically, with the log. These little bells,” pointing to twenty-four little bells overhead, “will quickly give warning of the entrance of water into any of the chambers. The equilibrium of the ship is denoted automatically by this alcohol cross combined with a double pendulum. The lipthalene pressure is given here. The many buttons and tubes communicate to all parts of the ship. Those two buttons release the iron weight at the bottom of the vessel, and these twelve buttons regulate the entry and exit of the water in the six water cylinders. The speed is regulated here, and the vessel steered by this little wheel;” and he pointed out the various instruments as he mentioned their uses. Cobb carefully examined every instrument as it was mentioned to him. Turning to Mr. Irwin, he asked:

“But where is your steersman—your lookout, I mean? Cooped up in this little room, you can see nothing around the ship. Even on deck, especially in rough weather, you would be too low down to have much of a view of your surroundings.”

“The explanation is most simple. Look into that box, if you please, and let your head fill the opening, to darken the interior.”

He smiled as he noted Cobb’s perplexed expression.

Obeying Mr. Irwin’s request, Cobb fitted his face to the opening and gazed inside the box. He saw the sea rising and falling in its swell, vessels passing in various directions, the faint blue outlines of the shore to the northwest, and—click, the scene changes: now other vessels in view, and a clear circle of the horizon, denoting a great expanse of water. Again a clicking sound, and—

“My God!” he cried, starting back; “a ship! a ship is almost upon us!”

Like lightning, Irwin sprang to the camera and glanced in; then quickly reaching out his hand, his fingers touched a button, and the hoarse marine whistle of the Tracer thundered forth its warning; seizing the tiller-wheel, he threw it hard aport, and then, without pausing, pressed another button, and the large gongs of the ship pealed out their summons to its crew that danger was imminent. Even as the alarm sounded, came a shock, a shiver, a slight careening of the vessel, and as Irwin took his white face from the camera, the grateful exclamation:

“Thank God! we are safe! Look! the monster passes by!”

Into the camera Cobb again peered; the dark, black stern of a large freighter was passing to the southwest.

Lieutenant Sibley and the crew of the Tracer were quickly huddled at the door of the pilot’s room.

“Lieutenant,” said Irwin, with a salute, “I confess that we have had a very narrow escape from being run down by a heavy freighter. Explaining these instruments to Mr. Cobb, I failed to note the approach of the vessel.”

The alarm having subsided, the subject was fully discussed, and Mr. Irwin was exonerated by the Lieutenant. All parties then returned to their various occupations.

Mr. Irwin then turned to Cobb and said:

“It was very negligent of me not to carefully survey the field for approaching vessels. The Tracer carries but a single mast, and sits so low in the water, that these many merchant ships, with their sleepy crews, often fail to sight her until too late to make a proper clearing.” Then returning to the subject upon which they had been speaking when Cobb’s excited exclamation had burst forth, he continued:

“I see that you have understood the object of the little dark box on the table. It is a camera-obscura. The single mast of the Tracer is of aluminum, strong, slight, and hollow, and rises to a height of twenty-eight feet. A lens at the top revolves by pushing this button; thus a perfect image of the surrounding water and all upon it is thrown on the white ground within the box. Sitting here and looking in the box, I note the proximity of objects and steer the vessel. The mast also serves to carry an arc light for night traveling, and our flag by day. Further, our air is drawn down through pipes in its interior; for, during heavy seas, we must have the air inlets far above the deck, which is constantly washed by the rollers.”

Some further conversation was indulged in, and then Cobb thanked Mr. Irwin for his kindness, excused himself, and was soon seated, with Lieutenant Sibley, in the latter’s cozy cabin.

Lunch having been disposed of, Rawolle, taking out his watch, remarked to Cobb: “In a few minutes we will be directly over Louisville, Kentucky; and in these few minutes, I will briefly explain the effects of the great cataclysm of 1916, as I promised to do: The gas strata of the Ohio basin,” he began, “extending from above Pittsburgh to the Mississippi River, with pockets innumerable and ramifications in every direction, contained millions of millions of cubic feet of gas under varying pressures from nil to many atmospheres. The catastrophe at Dillenback’s ignited the gas in what appeared to have been the main strata. Explosion followed explosion throughout the region now occupied by the Central Sea. The earth was rent and broken, and the great vacuums, caused by the annihilation of the gases, took away the support of the upper crust, and then atmospheric pressure completed the ruin. The earth sank and crushed into these voids until a new foundation was reached. In some sections the fall of the crust was frightful, terrific. In the vicinity of Cincinnati but one shock was felt, but that shock was terrible, horrible, annihilating. The earth sank 196 feet at one fall. Not a living soul escaped the shock of impact upon the underlying strata. The city was an inconceivable mass of ruins, and in two days, was covered with water. So it was over a region of 100,000 square miles, the earth sinking everywhere, but to different depths and with different rates of depression. Pittsburgh sank 377 feet, but so slowly that few lives were lost, though the destruction of property was very great. At the mouth of the Ohio the earth sank only one foot, increasing toward the east. Millions of lives were sacrificed and untold wealth lost, for the great depression commenced immediately to fill with the waters from the streams flowing into the Ohio basin, and from the underlying strata. Even the Mississippi turned its waters into the old mouth of the Ohio and flowed east, leaving but a small, shallow stream to flow in its old bed until augmented by the streams and rivers emptying into it below Cairo. Even with all these waters it was an insignificant river until it reached the Arkansas and received the mass of water from that river. But in 1918 the river was diverted back to its proper channel; though later on the dam was removed, owing to the rise in the Central Sea, and the natural outlet being at Cairo. This, in brief, Mr. Cobb, is the effect of a single accident in a gun factory, in 1916; though who can tell but that it might have occurred later on from some other cause?”

“But did not those who were not injured by the shocks and falling buildings have time to move their effects before the waters overtook them? for, surely, this immense sea did not fill up in a few days,” ventured Cobb.

“Along the Ohio, from this side of Louisville to above Cincinnati, scarcely any property was saved. The depression was such that the submergence came very quickly. But this was not the case in the surrounding country. In one week the shocks were over and the earth quiet. People recovered from their fears a little, and looked about them. Later on they commenced to rebuild, and it was not until a year after that they found a new foe against which they could not combat: the country was below the level of any outlet, natural or artificial, and was filling up into an inland sea. Surveys were made, and in 1918 the true condition of the country ascertained. Then, and only then, was it found that the region now covered by the Central Sea was destined to be lost to mankind. Human ingenuity could not solve the problem of drainage. There was no drainage. Far below the bed of the Mississippi, the only possible outlet, the country was doomed to inundation. The survey was completed and the true limits established. All within that area began to be abandoned. Property, wherever possible, was removed; but the buildings, at least those which could not be taken apart and moved, still remain under the sea as monuments of a once densely populated area. To be sure, the removal was not rapid. The exact time was known, from the surveys made, when the waters would gain their maximum height, or reach to any particular point.”

“Such an immense basin must have required a considerable time to fill up?” inquired Cobb.

“It did—years. It was a gala day at Cairo, and a day of rejoicing throughout the land, when, on the 14th of August, 1939, the Central Sea reached the dam at that city, and passed over in a gently increasing stream. The dam was removed, the channel opened, and navigation from the ocean to this immense body of water, through the mouth of the old Ohio River, was unobstructed.”

“Why,” exclaimed Cobb, in astonishment, “that was twenty-three years after the disturbances! It took longer to fill up than I had imagined.”

“The area lost,” continued Rawolle, “was about one hundred thousand square miles; the volume nearly one hundred and seventy-five trillion cubic feet. The water-shed of the Ohio produced ten billion cubic feet per day, all of which flowed into the Central Sea. The first two years the Mississippi discharged a like amount into the sunken area. It was estimated that over ninety trillion cubic feet of water were pushed up, so to speak, from the strata of the earth by the subsidence of the upper crust. Thus, one hundred trillion cubic feet of water rushed into the doomed basin of the Ohio in the first two years, making inundation very rapid during that time, and frightfully rapid during the first week. The Ohio water-shed supplied nearly four trillion cubic feet per year, which, to complete the seventy-five trillion necessary to fill the sea, took twenty-one years.”

“This is a most wonderful occurrence, and did I not have ocular proof of its reality, I admit I should be loath to believe it a possibility;” and Cobb seemed lost in a reverie of the marvelous events which had transpired during his long sleep on Mt. Olympus.

The tinkling of a bell caused Lieutenant Sibley, who had been writing at his desk, to look up and say:

“I presume we are near Louisville.”

Then, going to the tube, he answered Mr. Irwin, in the pilot-room, and was informed that the vessel was then over the city of Louisville.

The Tracer was soon brought to a rest, and Cobb witnessed the peculiar arrangements made for descending to the bottom of the sea. He watched every movement and noted every detail, and saw with what wonderful facility a thousand-ton ship could be made to obey a man’s will.

The mast of the Tracer was dropped until its top rested upon the deck of the vessel, its top closing automatically to prevent the ingress of water. A large circular float containing air-valves, and attached to a long hose, was loosened from its fastenings on the deck. The water cylinders were opened, and as they partially filled, the vessel lost its superiority of displacement and began to sink; the large float, with its air-valves, and attached to the hose, remained upon the top of the water, permitting air to be drawn down into the vessel by suction. Thus a constant supply of fresh air was obtained without recourse to the compressed air in store. In fact, the latter was never used except in emergencies or when it was desired, as in the case of war, to keep the approach of the vessel a secret.

The sensation of falling was apparent, but it was indescribably peculiar; neither pleasing, nor yet distasteful—such a feeling as when, in his boyhood days, he had sat upon the board of a swing and let the “old cat die.”

Passing with Lieutenant Sibley and the others into the pilot’s room, he saw the ease with which the descent was regulated, and noted the instrument showing the depth of submersion.

Mr. Irwin pressed a button, and Cobb felt the tremor of a forward movement. The displacement being but a trifle less than the weight of the vessel, the movements of the ship were now regulated by its engines and double rudders.

Stepping to the side of the room, the Lieutenant threw open the steel covering of a bull’s-eye, and then pressed the button near it. A brilliant flash shot out, and the rays penetrated the water for a considerable distance in every direction.

“There!” cried Lieutenant Sibley, with an involuntary wave of his hand. “Behold the city of the dead, Louisville!—Louisville, once such a grand city, now a silent, slime-covered, submerged testimony of nature’s conquering power over man’s puny will.”

Cobb pressed his face against the glass and silently gazed upon the lifeless buildings and streets of the city. Even as they stood years ago, so stood many at that moment. Others were in ruins, with gaping walls and broken doors and windows, and all were covered with mud and slime and marine vegetation.

The streets were half-way up to the second stories, but the tops of the street-lamps could be discerned sticking out of the muddy sediment which had been deposited over everything.

Slowly the Tracer moved forward, and the whole expanse of the southeast side of this unfortunate, but once brilliant, city was presented to view.

What emotions filled that man’s breast, with his eyes glued, as if fascinated by some unknown power, upon the spot he had, in years long since past, visited, looked upon, and walked in! With a sickening feeling of utter sadness at his heart, he turned away.

“God’s ways are inscrutable,” he sighed. A tear glistened in his eye as he cried: “No more! Let us ascend!”

At 24 dial the Tracer was at her moorings in Pittsburgh, and Cobb, Rawolle, and Lyman took the Chicago Pneumatic for Washington.

As he lay in his berth in the sleeper, his mind reverted back to the days when he had met his friends in social evenings of pleasure; to his old friend in Duke’s Lane, and to the bright, lovely face of that man’s daughter. Ah! how he longed for but an hour with them—an hour of true friendship and love; how he craved to listen to but a moment’s innocent prattle of his girl-love. Alone among strangers, among a people far ahead of his time, he felt that he was looked upon as a curiosity, but not as one claiming sympathy and love as a relative or dear friend. Did the experiment come up to the ideal? Was he satisfied to die and live again? He asked these questions of himself. He meditated—reflected—and slept.