The suggestion of the Star came like a revelation. It was accepted everywhere. Not only were these three vehicles the work of the same inventor; they were the same machine!

It was not easy to see how the remarkable transformation could be practically accomplished from one means of locomotion to the other. How could an automobile become a boat, and yet more, a submarine? All the machine seemed to lack was the power of flying through the air. Nevertheless, everything that was known of the three different machines, as to their size, their shape, their lack of odor or of steam, and above all their remarkable speed, seemed to imply their identity. The public, grown blase with so many excitements, found in this new marvel a stimulus to reawaken their curiosity.

The newspapers dwelt now chiefly on the importance of the invention. This new engine, whether in one vehicle or three, had given proofs of its power. What amazing proofs! The invention must be bought at any price. The United States government must purchase it at once for the use of the nation. Assuredly, the great European powers would stop at nothing to be beforehand with America, and gain possession of an engine so invaluable for military and naval use. What incalculable advantages would it give to any nation, both on land and sea! Its destructive powers could not even be estimated, until its qualities and limitations were better known. No amount of money would be too great to pay for the secret; America could not put her millions to better use.

But to buy the machine, it was necessary to find the inventor; and there seemed the chief difficulty. In vain was Lake Kirdall searched from end to end. Even its depths were explored with a sounding-line without result. Must it be concluded that the submarine no longer lurked beneath its waters? But in that case, how had the boat gotten away? For that matter, how had it come? An insoluble problem!

The submarine was heard from no more, neither in Lake Kirdall nor elsewhere. It had disappeared like the automobile from the roads, and like the boat from the shores of America. Several times in my interviews with Mr. Ward, we discussed this matter, which still filled his mind. Our men continued everywhere on the lookout, but as unsuccessfully as other agents.

On the morning of the twenty-seventh of June, I was summoned into the presence of Mr. Ward.

"Well, Strock," said he, "here is a splendid chance for you to get your revenge."

"Revenge for the Great Eyrie disappointment?"

"Of course."

"What chance?" asked I, not knowing if he spoke seriously, or in jest.

"Why, here," he answered. "Would not you like to discover the inventor of this three-fold machine?"

"I certainly should, Mr. Ward. Give me the order to take charge of the matter, and I will accomplish the impossible, in order to succeed. It is true, I believe it will be difficult."

"Undoubtedly, Strock. Perhaps even more difficult than to penetrate into the Great Eyrie."

It was evident that Mr. Ward was intent on rallying me about my unsuccess. He would not do that, I felt assured, out of mere unkindness. Perhaps then he meant to rouse my resolution. He knew me well; and realized that I would have given anything in the world to recoup my defeat. I waited quietly for new instructions.

Mr. Ward dropped his jesting and said to me very generously, "I know, Strock, that you accomplished everything that depended on human powers; and that no blame attaches to you. But we face now a matter very different from that of the Great Eyrie. The day the government decides to force that secret, everything is ready. We have only to spend some thousands of dollars, and the road will be open."

"That is what I would urge."

"But at present," said Mr. Ward, shaking his head, "it is much more important to place our hands on this fantastic inventor, who so constantly escapes us. That is work for a detective, indeed; a master detective!"

"He has not been heard from again?"

"No; and though there is every reason to believe that he has been, and still continues, beneath the waters of Lake Kirdall, it has been impossible to find any trace of him anywhere around there. One would almost fancy he had the power of making himself invisible, this Proteus of a mechanic!"

"It seems likely," said I, "that he will never be seen until he wishes to be."

"True, Strock. And to my mind there is only one way of dealing with him, and that is to offer him such an enormous price that he cannot refuse to sell his invention."

Mr. Ward was right. Indeed, the government had already made the effort to secure speech with this hero of the day, than whom surely no human being has ever better merited the title. The press had widely spread the news, and this extraordinary individual must assuredly know what the government desired of him, and how completely he could name the terms he wished.

"Surely," added Mr. Ward, "this invention can be of no personal use to the man, that he should hide it from the rest of us. There is every reason why he should sell it. Can this unknown be already some dangerous criminal who, thanks to his machine, hopes to defy all pursuit?"

My chief then went on to explain that it had been decided to employ other means in search of the inventor. It was possible after all that he had perished with his machine in some dangerous maneuver. If so, the ruined vehicle might prove almost as valuable and instructive to the mechanical world as the man himself. But since the accident to the schooner "Markel" on Lake Kirdall, no news of him whatever had reached the police.

On this point Mr. Ward did not attempt to hide his disappointment and his anxiety. Anxiety, yes, for it was manifestly becoming more and more difficult for him to fulfill his duty of protecting the public. How could we arrest criminals, if they could flee from justice at such speed over both land and sea? How could we pursue them under the oceans? And when dirigible balloons should also have reached their full perfection, we would even have to chase men through the air! I asked myself if my colleagues and I would not find ourselves some day reduced to utter helplessness? If police officials, become a useless incumbrance, would be definitely discarded by society?

Here, there recurred to me the jesting letter I had received a fortnight before, the letter which threatened my liberty and even my life. I recalled, also, the singular espionage of which I had been the subject. I asked myself if I had better mention these things to Mr. Ward. But they seemed to have absolutely no relation to the matter now in hand. The Great Eyrie affair had been definitely put aside by the government, since an eruption was no longer threatening. And they now wished to employ me upon this newer matter. I waited, then, to mention this letter to my chief at some future time, when it would be not so sore a joke to me.

Mr. Ward again took up our conversation. "We are resolved by some means to establish communication with this inventor. He has disappeared, it is true; but he may reappear at any moment, and in any part of the country. I have chosen you, Strock, to follow him the instant he appears. You must hold yourself ready to leave Washington on the moment. Do not quit your house, except to come here to headquarters each day; notify me, each time by telephone, when you start from home, and report to me personally the moment you arrive here."

"I will follow orders exactly, Mr. Ward," I answered. "But permit me one question. Ought I to act alone, or will it not be better to join with me?"

"That is what I intend," said the chief, interrupting me. "You are to choose two of our men whom you think the best fitted."

"I will do so, Mr. Ward. And now, if some day or other I stand in the presence of our man, what am I to do with him?"

"Above all things, do not lose sight of him. If there is no other way, arrest him. You shall have a warrant."

"A useful precaution, Mr. Ward. If he started to jump into his automobile and to speed away at the rate we know of, I must stop him at any cost. One cannot argue long with a man making two hundred miles an hour!"

"You must prevent that, Strock. And the arrest made, telegraph me. After that, the matter will be in my hands."

"Count on me, Mr. Ward; at any hour, day or night, I shall be ready to start with my men. I thank you for having entrusted this mission to me. If it succeeds, it will be a great honor--"

"And of great profit," added my chief, dismissing me.

Returning home, I made all preparations for a trip of indefinite duration. Perhaps my good housekeeper imagined that I planned a return to the Great Eyrie, which she regarded as an ante-chamber of hell itself. She said nothing, but went about her work with a most despairing face. Nevertheless, sure as I was of her discretion, I told her nothing. In this great mission I would confide in no one.

My choice of the two men to accompany me was easily made. They both belonged to my own department, and had many times under my direct command given proofs of their vigor, courage and intelligence. One, John Hart, of Illinois, was a man of thirty years; the other, aged thirty-two, was Nab Walker, of Massachusetts. I could not have had better assistants.

Several days passed, without news, either of the automobile, the boat, or the submarine. There were rumors in plenty; but the police knew them to be false. As to the reckless stories that appeared in the newspapers, they had most of them, no foundation whatever. Even the best journals cannot be trusted to refuse an exciting bit of news on the mere ground of its unreliability.

Then, twice in quick succession, there came what seemed trustworthy reports of the "man of the hour." The first asserted that he had been seen on the roads of Arkansas, near Little Rock. The second, that he was in the very middle of Lake Superior.

Unfortunately, these two notices were absolutely unreconcilable; for while the first gave the afternoon of June twenty-sixth, as the time of appearance, the second set it for the evening of the same day. Now, these two points of the United States territory are not less than eight hundred miles apart. Even granting the automobile this unthinkable speed, greater than any it had yet shown, how could it have crossed all the intervening country unseen? How could it traverse the States of Arkansas, Missouri, Iowa and Wisconsin, from end to end without anyone of our agents giving us warning, without any interested person rushing to a telephone?

After these two momentary appearances, if appearances they were, the machine again dropped out of knowledge. Mr. Ward did not think it worth while to dispatch me and my men to either point whence it had been reported.

Yet since this marvelous machine seemed still in existence, something must be done. The following official notice was published in every newspaper of the United States under July 3d. It was couched in the most formal terms.

"During the month of April, of the present year, an automobile traversed the roads of Pennsylvania, of Kentucky, of Ohio, of Tennessee, of Missouri, of Illinois; and on the twenty-seventh of May, during the race held by the American Automobile Club, it covered the course in Wisconsin. Then it disappeared.

"During the first week of June, a boat maneuvering at great speed appeared off the coast of New England between Cape Cod and Cape Sable, and more particularly around Boston. Then it disappeared.

"In the second fortnight of the same month, a submarine boat was run beneath the waters of Lake Kirdall, in Kansas. Then it disappeared.

"Everything points to the belief that the same inventor must have built these three machines, or perhaps that they are the same machine, constructed so as to travel both on land and water.

"A proposition is therefore addressed to the said inventor, whoever he be, with the aim of acquiring the said machine.

"He is requested to make himself known and to name the terms upon which he will treat with the United States government. He is also requested to answer as promptly as possible to the Department of Federal Police, Washington, D. C., United States of America."

Such was the notice printed in large type on the front page of every newspaper. Surely it could not fail to reach the eye of him for whom it was intended, wherever he might be. He would read it. He could scarce fail to answer it in some manner. And why should he refuse such an unlimited offer? We had only to await his reply.

One can easily imagine how high the public curiosity rose. From morning till night, an eager and noisy crowd pressed about the bureau of police, awaiting the arrival of a letter or a telegram. The best reporters were on the spot. What honor, what profit would come to the paper which was first to publish the famous news! To know at last the name and place of the undiscoverable unknown! And to know if he would agree to some bargain with the government! It goes without saying that America does things on a magnificent scale. Millions would not be lacking for the inventor. If necessary all the millionaires in the country would open their inexhaustible purses!

The day passed. To how many excited and impatient people it seemed to contain more than twenty-four hours! And each hour held far more than sixty minutes! There came no answer, no letter, no telegram! The night following, there was still no news. And it was the same the next day and the next.

There came, however another result, which had been fully foreseen. The cables informed Europe of what the United States government had done. The different Powers of the Old World hoped also to obtain possession of the wonderful invention. Why should they not struggle for an advantage so tremendous? Why should they not enter the contest with their millions?

In brief, every great Power took part in the affair, France, England, Russia, Italy, Austria, Germany. Only the states of the second order refrained from entering, with their smaller resources, upon a useless effort. The European press published notices identical with that of the United States. The extraordinary "chauffeur" had only to speak, to become a rival to the Vanderbilts, the Astors, the Goulds, the Morgans, and the Rothschilds of every country of Europe.

And, when the mysterious inventor made no sign, what attractive offers were held forth to tempt him to discard the secrecy in which he was enwrapped! The whole world became a public market, an auction house whence arose the most amazing bids. Twice a day the newspapers would add up the amounts, and these kept rising from millions to millions. The end came when the United States Congress, after a memorable session, voted to offer the sum of twenty million dollars. And there was not a citizen of the States of whatever rank, who objected to the amount, so much importance was attached to the possession of this prodigious engine of locomotion. As for me, I said emphatically to my old housekeeper: "The machine is worth even more than that."

Evidently the other nations of the world did not think so, for their bids remained below the final sum. But how useless was this mighty struggle of the great rivals! The inventor did not appear! He did not exist! He had never existed! It was all a monstrous pretense of the American newspapers. That, at least, became the announced view of the Old World.

And so the time passed. There was no further news of our man, there was no response from him. He appeared no more. For my part, not knowing what to think, I commenced to lose all hope of reaching any solution to the strange affair.

Then on the morning of the fifteenth of July, a letter without postmark was found in the mailbox of the police bureau. After the authorities had studied it, it was given out to the Washington journals, which published it in facsimile, in special numbers. It was couched as follows: