the submarine boat mermaid was a cigar-shaped shell of aluminium bronze, extremely light and strong, about forty feet in length and eight in greatest diameter. on its upper side was a small railed platform or deck, from the centre of which rose a low turret provided with four bull's-eyes, from which an observer might glance out ahead, astern, or on either side. another bull's-eye was fitted into the hinged and water-tight cap that closed the turret when the boat was submerged.
the interior of the boat was divided into three compartments. of these, the one farthest forward was fitted with an air-lock, through which a person wearing a diver's suit might leave the vessel while she was under water and return to her at will. this hold was also pierced for a bull's-eye through which could be made to shine an electric search light of intense power.
the central compartment was the living and operating room. it also contained a dynamo, an air compressor, and a small condenser, by means of which sea-water could be made drinkable. in the after compartment was located a compact but powerful gasoline engine. this furnished the motive power for running on the surface, and also stored electricity by which the screw could be turned when surface air was no longer available. beneath the floor of the central compartment was a tank for water ballast, which could be filled or emptied at will of the operator. in all parts of the boat were hundreds of tubes, wires, cocks, valves, and other devices of amazing ingenuity for ensuring the safety of her crew and the discomfiture of an enemy.
she was indeed, as carlos moranza had said, one of the crowning scientific marvels of the century. on the day succeeding that of her trial trip, the young cuban was full of hope and courage, for professor rivers had been won to his cause by the enticing prospect of achieving the rescue of a young girl from a dreadful fate, and at the same time testing under most trying conditions the powers of his beloved boat. he had only stipulated that she should not be used for the destruction of either life or property.
thus it happened that in less than a week one of the most powerful tugs on the delaware cleared for havana. she had in tow a great dumping scow, such as is used in new york harbour for conveying the city garbage far out to sea. this scow was built with a long central pocket, the bottom of which was longitudinally divided into two parts. each of these was hung on massive hinges, and could be made to drop or open outward, thus allowing the contents of the pocket to fall into the sea. then, by means of a donkey-engine, the great valves could be drawn up and closed as before.
the question of how to get the mermaid to havana had proved most puzzling. she was too small to undertake such a voyage by herself, and had she been shipped on the deck of another vessel, her every movement would have been watched and heralded, while the success of the proposed expedition depended upon its secrecy. thus, at the very outset, the would-be rescuers seemed to be confronted by an insurmountable difficulty. then carl baldwin had thought of the sea-going dumping scows, several of which had been built in his father's shipyard, where one recently completed even now awaited a purchaser.
"why couldn't we take the mermaid to cuba in it?" he suggested, after several other plans had been dismissed as impracticable.
"the very thing," cried carlos moranza. "in that way we could carry her right into havana harbour, and there offer the scow for sale to the spaniards as a blind. it is a noble idea, my carol, and will prove our salvation."
"it might be done," said the professor thoughtfully. "let us go and take some measurements."
this they did, and found that the pocket of the dumping scow was amply large to hold the mermaid, at the same time allowing her free egress and exit. it would even float her when closed and half filled with water. only a few alterations that readily suggested themselves to the professor were needed to exactly suit the great craft to their purpose.
while he took charge of these, and carlos took a trip to new york for consultation with the president of the cuban junta, carl baldwin arranged for the charter of the finest sea-going tug on the delaware, and through her captain for the purchase of the dumping-scow.
the professor had long since placed the practical direction of his school in the hands of able assistants, so that he was free to leave it at a moment's notice for any length of time. thus, when he announced that he was about to devote a few weeks to the testing of his pet invention, and should need the assistance of his two ranking pupils, their departure was effected without arousing undue curiosity.
the clearing of the tug, with its novel tow, for havana, was, however, quite another thing; and, from the moment their destination was announced, both craft were watched by government officials and spanish spies to see that no contraband cargo was taken aboard. of course nothing of the kind was found; but this did not prevent a revenue cutter from escorting the tow down the river and across delaware bay until it was clear of the breakwater and well out at sea. finally, the cutter turned back; but even then her commander continued to watch the tow through a glass.
"in spite of their seeming innocence, i regard that as one of the most suspicious departures ever made from the delaware," he remarked to a lieutenant who stood beside him. "the pretence of trying to sell that scow in havana is only the baldest kind of a bluff. any fool knows that those blooming spaniards aren't going to put themselves to either the expense or trouble of carrying garbage out to sea so long as they can dump it in their harbours. hello! what's that? look quick and tell me if you don't see something between us and them."
through the glass thrust into his hand, the lieutenant took a long and comprehensive survey of the intervening waters.
"no, sir, i don't see anything," he reported at length.
"neither do i now," said the other after another look. "i would have sworn, though, that i saw something like a raft moving towards that scow."
the commander had indeed caught a glimpse of the mermaid rising to the surface to get her bearings, but she had instantly dived, nor did she again visit the surface until safely within the shadow of the great scow.
she had run down the river the night before, and had lain behind the breakwater with only a small portion of her turret above the surface, until the tow, with its accompanying cutter, had passed out to sea. then she followed, with her eyes just awash, and dove deep beneath the revenue vessel when it turned back. upon next coming to the surface, she had been allowed to rise a little too far, and so was very nearly discovered.
"it was a close shave," admitted carl baldwin, after the mermaid was safely ensconced within the closed pocket of the great scow; "but a safe miss is as good as a thousand miles, and now we are all right till we get to havana."
"don't you be too sure of that," admonished the captain of the tug gruffly. "there's many a cruiser between here and there, and every one of 'em is sartin to board us."
so it proved. at charleston, where the tug put in for coal, leaving her tow in the lower bay, the scow was boarded by revenue officers, who did not leave her until she was again at sea; and all the while the poor little mermaid was dodging about under water, only coming up now and then for a breath and a quick glance at her surroundings, like a hunted sea-fowl.
off the mouth of the st. john's river, the tow was hove-to by a blank shot from a government cruiser, and again was the mermaid forced to seek safety at the bottom of the sea. this time she avenged herself by rising directly beneath the cruiser, and demonstrating to the professor's entire satisfaction how easily he could if he chose place and fire a torpedo that would blow her from the water.
it had been decided to touch at key west, the most southerly extremity of florida, as well as of the united states, and only eighty-five miles across the gulf stream from havana, and finally, after many narrow escapes from discovery, our adventurers reached the port of that quaint island-city in safety.
here they found several american men-of-war, a small fleet of torpedo-boats, four revenue cutters, and a spanish cruiser, to all of whom the strange tow, slowly making its way up the harbour, seemed an object of especial interest. their fame had preceded them; every one knew that they were bound for havana, and that they had been objects of suspicion all the way down the coast. so, before they came to anchor, they were boarded by united states officers, and a guard was placed on both tug and scow, with orders to allow no communication between them and the shore, except under strict surveillance.
in the meantime, the little mermaid had sunk quietly out of sight, nor did she again rise to the surface until safely beneath a wharf covered with freight sheds, that extended out to deep water. here, hidden in deepest shadow, she lay unobserved until nightfall, when our lads found no difficulty in gaining the streets of the town, leaving the professor in charge of his beloved boat.
as carlos moranza had visited key west before, he led the way without hesitation amid throngs of promenaders, among whom white was the rarest colour to be seen. coal-black negroes from jamaica, sallow-complexioned spaniards, swarthy cubans, mulattoes, quadroons, octoroons, and creoles, with faces tinted in every shade of brown or yellow, jostled each other on the side-walks, all talking, singing, or laughing, with eager gesticulations. electric lights gleamed among the softly nestling leaves of tall cocoa-palms. open carriages, bearing cigarette-smoking men in white linen, gaudily-clad negresses, or languid cuban women, whose only sign of animation lay in their flashing eyes, rattled over the white pavements, while, above all, innumerable flags, displaying the blue and white stripes, the crimson field and single white star of cuba libre, fluttered in the faint night breeze.
the entire city, which is wholly cuban in sympathy, as well as two-thirds so in population, was rejoicing over the news just received of an insurgent victory. the exulting throngs were most dense about the building occupied by an agent of the cuban junta, on a balcony of which the glad tidings were being read aloud from a paper just snatched off the press, while a guard stationed at the main entrance forbade admission, except to such persons as were of well-attested patriotism.
"halt! you may not pass!" cried one of these, as our lads, having forced their way through the crowd, sought to enter.
for answer carlos moranza spoke a few words in so low a tone that only he might hear them.
"the strange tow, slowly making its way up the harbour."
instantly the man stood aside, touched his cap respectfully, and motioned them to enter.
as they did so, a third person attempted to pass the guard in their company, but was seized on the threshold.
"is this hombre of your party, se?or?" asked the guard.
"certainly not," replied carlos. "i never saw him before."
so the intruder, who was evidently of spanish blood, was ignominiously thrust back, and as he slunk away he muttered words that boded no good to carlos moranza, in case they should again meet.
in the meantime the young cuban, accompanied by carl baldwin, made his way to the balcony where the agent of the junta had just finished reading of garcia's victory. as carlos touched him on the shoulder he turned quickly and frowned at sight of a stranger. again the lad whispered his magic formula, and in another moment the agent was embracing him with the fervour of a life-long friendship. then he led his guests to a private room, where for half-an-hour he engaged carlos in earnest conversation, of which young baldwin could only understand an occasional word.
when our lads finally left the building and regained the street, the latter asked curiously, "what was it all about, old man?"
"he said," replied carlos, "that the spanish cruiser now in port is here for the express purpose of escorting us to havana, and that, as soon as we are outside key west harbour, she will place a guard on both tug and scow."
"hm!" remarked carl baldwin reflectively; "we can't allow that."
"i should say not," agreed carlos moranza; "only i'd like to know how we are to prevent it."
"just you leave it to me, and i'll show you the trick," rejoined the young american.
