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.