Metcalf plotted a new course, designed to intercept that of the mysterious craft, and went on, so elated by the news he had heard that he took his gossipy young executive into his confidence.

"Mr. Smith," he said, "that sealer described one of the new seagoing submersibles of the Japanese, did he not?"

"Yes, sir, I think he did--a larger submarine, without any conning-tower and the old-fashioned periscope. They have seven thousand miles'

cruising radius, enough to cross the Pacific."

By asking questions of various craft, and by diligent use of a telescope, Metcalf found his quarry three days later--a log-like object on the horizon, with the slim white pole amidships and the excrescence near its base.

"Wait till I get his bearing by compass," said Metcalf to his chief officer, "then we'll smoke up our specs and run down on him. Signal him by the International Code to put out his light, and to heave to, or we'll sink him."

Mr. Smith bowed to his superior, found the numbers of these commands in the code book, and with a string of small flags at the signal-yard, and every man aboard viewing the world darkly through a smoky film, the torpedo-boat approached the stranger at thirty knots. But there was no blinding glare of light in their eyes, and when they were within a hundred yards of the submersible, Metcalf removed his glasses for a moment's distinct vision. Head and shoulders out of a hatch near the tube was a man waving a white handkerchief. He rang the stopping bells.

"He surrenders, Mr. Smith," he said, joyously, "and without firing a torpedo!"

He examined the man through the telescope and laughed.

"I know him," he said. Then funneling his hands, he hailed:

"Do you surrender to the United States of America?"

"I surrender," answered the man. "I am helpless."

"Then come aboard without arms. I'll send a boat."

A small dinghy-like boat was dispatched, and it returned with the man, a Japanese in lieutenant's uniform, whose beady eyes twinkled in alarm as Metcalf greeted him.

"Well, Saiksi, you perfected it, didn't you?--my invisible searchlight, that I hadn't money to go on with."

The Jap's eyes sought the deck, then resumed their Asiatic steadiness.

"Metcalf--this you," he said, "in command? I investigated and heard you had resigned to become a doctor."

"But I came back to the service, Saiksi. Thanks to you and your light--my light, rather--I am in command here in place of men you blinded. Saiksi, you deserve no consideration from me, in spite of our rooming together at Annapolis. You took--I don't say stole--my invention, and turned it against the country that educated you. You, or your _confreres_, did this before a declaration of war. You are a pirate, and I could string you up to my signal-yard and escape criticism."

"I was under orders from my superiors, Captain Metcalf."

"They shall answer to mine. You shall answer to me. How many boats have you equipped with my light?"

"There are but three. It is very expensive."

"One for our Philippine squadron, one for the Hawaiian, and one for the coast. You overdid things, Saiksi. If you hadn't set fire to that sealer the other day, I might not have found you. It was a senseless piece of work that did you no good. Oh, you are a sweet character! How do you get your ultraviolet rays--by filtration or prismatic dispersion?"

"By filtration."

"Saiksi, you're a liar as well as a thief. The colored lights you use to attract attention are the discarded rays of the spectrum. No wonder you investigated me before you dared flash such a decoy! Well, I'm back in the navy, and I've been investigating you. As soon as I heard of the first symptom of sunburn, I knew it was caused by the ultraviolet rays, the same as from the sun; and I knew that nothing but my light could produce those rays at night time. And as a physician I knew what I did not know as an inventor--the swift amblyopia that follows the impact of this light on the retina. As a physician, too, I can inform you that your country has not permanently blinded a single American seaman or officer. The effects wear off."

The Jap gazed stolidly before him while Metcalf delivered himself of this, but did not reply.

"Where is the Japanese fleet bound?" he asked, sternly.

"I do not know."

"And would not tell, whether you knew or not. But you said you were helpless. What has happened to you? You can tell that."

"A simple thing, Captain Metcalf. My supply of oil leaked away, and my engines must work slowly. Your signal was useless; I could not have turned on the light."

"You have answered the first question. You are far from home without a mother-ship, or she would have found you and furnished oil before this.

You have come thus far expecting the fleet to follow and strike a helpless coast before your supplies ran out."

Again the Jap's eyes dropped in confusion, and Metcalf went on.

"I can refurnish your boat with oil, my engineer and my men can handle her, and I can easily learn to manipulate your--or shall I say _our_--invisible searchlight. Hail your craft in English and order all hands on deck unarmed, ready for transshipment to this boat. I shall join your fleet myself."

A man was lounging in the hatchway of the submersible, and this man Saiksi hailed.

"Ae-hai, ae-hai, Matsu. We surrender. We are prisoner. Call up all men onto the deck. Leave arms behind. We are prisoner."

They mustered eighteen in all, and in half an hour they were ironed in a row along the stanchioned rail of the torpedo-boat.

"You, too, Saiksi," said Metcalf, coming toward him with a pair of jingling handcuffs.

"Is it not customary, Captain Metcalf," said the Jap, "to parole a surrendered commander?"

"Not the surrendered commander of a craft that uses new and deadly weapons of war unknown to her adversary, and before the declaration of war. Hold up your hands. You're going into irons with your men. All Japs look alike to me, now."

So Lieutenant Saiksi, of the Japanese navy, was ironed beside his cook and meekly sat down on the deck. With the difference of dress, they really did look alike.

Metcalf had thirty men in his crew. With the assistance of his engineer, a man of mechanics, he picked eighteen of this crew and took them and a barrel of oil aboard the submersible. Then for three days the two craft lay together, while the engineer and the men familiarized themselves with her internal economy--the torpedo-tubes, gasoline-engines, storage-batteries, and motors; and the vast system of pipes, valves, and wires that gave life and action to the boat--and while Metcalf experimented with the mysterious searchlight attached to the periscope tube invented by himself, but perfected by others. Part of his investigation extended into the night. Externally, the light resembled a huge cup about two feet in diameter, with a thick disk fitted around it in a vertical plane. This disk he removed; then, hailing Smith to rig his fire-hose and get off the deck, he descended the hatchway and turned on the light, viewing its effects through the periscope. This, be it known, is merely a perpendicular, non-magnifying telescope that, by means of a reflector at its upper end, gives a view of the seascape when a submarine boat is submerged. And in the eyepiece at its base Metcalf beheld a thin thread of light, of such dazzling brilliancy as to momentarily blind him, stretch over the sea; but he put on his smoked glasses and turned the apparatus, tube and all, until the thin pencil of light touched the end of the torpedo-boat's signal-yard. He did not need to bring the two-inch beam to a focus; it burst into flame and he quickly shut off the light and shouted to Smith to put out the fire--which Smith promptly did, with open comment to his handful of men on this destruction of Government property.

"Good enough!" he said to Smith, when next they met. "Now if I'm any good I'll give the Japs a taste of their own medicine."

"Take me along, captain," burst out Smith in sudden surrender. "I don't understand all this, but I want to be in it."

"No, Mr. Smith. The chief might do your work, but I doubt that you could do his. I need him; so you can take the prisoners home. You will undoubtedly retain command."

"Very good, sir," answered the disappointed youngster, trying to conceal his chagrin.

"I don't want you to feel badly about it. I know how you all felt toward me. But I'm on a roving commission. I have no wireless apparatus and no definite instructions. I've been lampooned and ridiculed in the papers, and I'm going to give them my answer--that is, as I said, if I'm any good. If I'm not I'll be sunk."

So when the engineer had announced his mastery of his part of the problem, and that there was enough of gasoline to cruise for two weeks longer, Smith departed with the torpedo-boat, and Metcalf began his search for the expected fleet.

It was more by good luck than by any possible calculation that Metcalf finally found the fleet. A steamer out of San Francisco reported that it had not been heard from, and one bound in from Honolulu said that it was not far behind--in fact had sent a shot or two. Metcalf shut off gasoline, waited a day, and saw the smoke on the horizon. Then he submerged to the awash condition, which in this boat just floated the searchlight out of water; and thus balanced, neither floating nor sinking nor rolling, but rising and falling with the long pulsing of the ground-swell, he watched through the periscope the approach of the enemy.

It was an impressive spectacle, and to a citizen of a threatened country a disquieting one. Nine high-sided battle-ships of ten-gun type--nine floating forts, each one, unopposed, able to reduce to smoking ruin a city out of sight of its gunners; each one impregnable to the shell fire of any fortification in the world, and to the impact of the heaviest torpedo yet constructed--they came silently along in line-ahead formation, like Indians on a trail. There were no compromises in this fleet. Like the intermediate batteries of the ships themselves, cruisers had been eliminated and it consisted of extremes, battle-ships, and torpedo-boats, the latter far to the rear. But between the two were half a dozen colliers, repair, and supply ships.

Night came down before they were near enough for operations, and Metcalf turned on his invisible light, expanding the beam to embrace the fleet in its light, and moved the boat to a position about a mile away from its path. It was a weird picture now showing in the periscope: each gray ship a bluish-green against a background of black marked here and there by the green crest of a breaking sea. Within Metcalf's reach were the levers, cranks, and worms that governed the action of the periscope and the light; just before him were the vertical and horizontal steering-wheels; under these a self-illuminating compass, and at his ear a system of push-buttons, speaking-tubes, and telegraph-dials that put him in communication with every man on the boat, each one of whom had his part to play at the proper moment, but not one of whom could see or know the result. The work to be done was in Metcalf's hands and brain, and, considering its potentiality, it was a most undramatic performance.

He waited until the leading flag-ship was within half a mile of being abreast; then, turning on a hanging electric bulb, he held it close to the eyepiece of the periscope, knowing that the light would go up the tube through the lenses and be visible to the fleet. And in a moment he heard faintly through the steel walls the sound transmitted by the sea of a bugle-call to quarters. He shut off the bulb, watched a wandering shaft of light from the flag-ship seeking him, then contracted his own invisible beam to a diameter of about three feet, to fall upon the flag-ship, and played it back and forth, seeking gun ports and apertures and groups of men, painting all with that blinding light that they could not see, nor immediately sense. There was nothing to indicate that he had succeeded; the faces of the different groups were still turned his way, and the futile searchlight still wandered around, unable to bring to their view the white tube with its cup-like base.