He had been in Toledo on a wholly different mission, when chance had thrown him on the track of the "Terror."

We drove rapidly along the shore of Lake Erie, toward the southwest. This inland sea of water is on the northern boundary of the United States, lying between Canada on one side and the States of Ohio, Pennsylvania and New York on the other. If I stop to mention the geographical position of this lake, its depth, its extent, and the waters nearest around, it is because the knowledge is necessary for the understanding of the events which were about to happen.

The surface of Lake Erie covers about ten thousand square miles. It is nearly six hundred feet above sea level. It is joined on the northwest, by means of the Detroit River, with the still greater lakes to the westward, and receives their waters. It has also rivers of its own though of less importance, such as the Rocky, the Cuyahoga, and the Black. The lake empties at its northeastern end into Lake Ontario by means of Niagara River and its celebrated falls.

The greatest known depth of Lake Erie is over one hundred and thirty feet. Hence it will be seen that the mass of its waters is considerable. In short, this is a region of most magnificent lakes. The land, though not situated far northward, is exposed to the full sweep of the Arctic cold. The region to the northward is low, and the winds of winter rush down with extreme violence. Hence Lake Erie is sometimes frozen over from shore to shore.

The principal cities on the borders of this great lake are Buffalo at the east, which belongs to New York State, and Toledo in Ohio, at the west, with Cleveland and Sandusky, both Ohio cities, at the south. Smaller towns and villages are numerous along the shore. The traffic is naturally large, its annual value being estimated at considerably over two million dollars.

Our carriage followed a rough and little used road along the borders of the lake; and as we toiled along, Arthur Wells told me, what he had learned.

Less than two days before, on the afternoon of July twenty-seventh Wells had been riding on horseback toward the town of Herly. Five miles outside the town, he was riding through a little wood, when he saw, far up across the lake, a submarine which rose suddenly above the waves. He stopped, tied his horse, and stole on foot to the edge of the lake. There, from behind a tree he had seen with his own eyes seen this submarine advance toward him, and stop at the mouth of Black Rock Creek. Was it the famous machine for which the whole world was seeking, which thus came directly to his feet?

When the submarine was close to the rocks, two men climbed out upon its deck and stepped ashore. Was one of them this Master of the World, who had not been seen since he was reported from Lake Superior? Was this the mysterious "Terror" which had thus risen from the depths of Lake Erie?

"I was alone," said Wells. "Alone on the edge of the Creek. If you and your assistants, Mr. Strock had been there, we four against two, we would have been able to reach these men and seize them before they could have regained their boat and fled."

"Probably," I answered. "But were there no others on the boat with them? Still, if we had seized the two, we could at least have learned who they were."

"And above all," added Wells, "if one of them turned out to be the captain of the 'Terror!'"

"I have only one fear, Wells; this submarine, whether it is the one we seek or another, may have left the creek since your departure."

"We shall know about that in a few hours, now. Pray Heaven they are still there! Then when night comes?"

"But," I asked, "did you remain watching in the wood until night?"

"No; I left after an hour's watching, and rode straight for the telegraph station at Toledo. I reached there late at night and sent immediate word to Washington."

"That was night before last. Did you return yesterday to Black Rock Creek?"

"Yes."

"The submarine was still there?"

"In the same spot."

"And the two men?"

"The same two men. I judge that some accident had happened, and they came to this lonely spot to repair it."

"Probably so," said I. "Some damage which made it impossible for them to regain their usual hiding-place. If only they are still here!"

"I have reason to believe they will be, for quite a lot of stuff was taken out of the boat, and laid about upon the shore; and as well as I could discern from a distance they seemed to be working on board."

"Only the two men?"

"Only the two."

"But," protested I, "can two be sufficient to handle an apparatus of such speed, and of such intricacy, as to be at once automobile, boat and submarine?"

"I think not, Mr. Strock; but I only saw the same two.