I replied, enthusiastically. "Then you'll go down to Nitropolis?" queried MacLeod, eagerly. "You can catch a train that will get you there about noon. And the company will pay you well." "MacLeod, with the mystery, Miss Snedden, and the remuneration, you are irresistible," smiled Kennedy. "Thank you," returned the detective. "You won't regret it.

In almost no time, so accurately did he keep his fingers on the fevered pulse of Nitropolis, MacLeod had found out that Gertrude had been seen driving away from the company's grounds with some one in Garretson's car, probably Garretson himself. Jackson had been seen hurrying down the street. Some one else had seen Ida Snedden in Jackson's car, alone.

Meanwhile, over the wire, MacLeod had sent out descriptions of the four people and the two cars, in the hope of intercepting them before they could be plunged into the obscurity of any near-by city. Not content with that, MacLeod and Kennedy started out in the former's car, while I climbed in with Snedden, and we began a systematic search of the roads out of Nitropolis.

By the time the vehicle arrived he had hurriedly packed up some apparatus in two large grips, one of which it fell to my lot to carry. The trip down to Nitropolis was uninteresting, and we arrived at the little station shortly after noon.

MacLeod looked at us inquiringly, and Kennedy nodded to go on, though I am sure neither of us was familiar with the place. "They've called the new plant Nitropolis rather a neat name for a powder-works, don't you think?" resumed MacLeod. "Everything went along all right until a few days ago. Then one of the buildings, a storehouse, was blown up.

Startling as was the revelation of an actual phantom destroyer, our minds were more aroused as to who might be the criminal who had employed such an engine of death. Kennedy drew from his pocket the telegram which had just arrived, and spread it out flat before us on a table. It was dated Philadelphia, and read: MRS. IDA SNEDDEN, Nitropolis: Garretson and Gertrude were married to-day.

"Guy Fawkes himself would shudder in that mill. Think of it five explosions on five successive days, and not a clue!" Our visitor had presented a card bearing the name of Donald MacLeod, chief of the Nitropolis Powder Company's Secret Service. It was plain that he was greatly worried over the case about which he had at last been forced to consult Kennedy.

Knowing human nature, Kennedy was careful to be struck with admiration and amazement at everything we had seen in our brief whirl through Nitropolis. It was not a difficult or entirely assumed feeling, either, when one realized that, only a few short months before, the region had been nothing better than an almost hopeless wilderness of scrub-pines.