After anxious thought he decided to take the lesser risk. He would not bring assistants into the matter, but would trust to his own skill to carry on the investigation unnoticed by the distiller.

Though the discovery of Archer’s identity seemed greatly to strengthen the probability that the secret telephone led to him, Willis could not state this positively, and he felt it was the next point to be ascertained. The same argument that he had used before seemed to apply—that owing to the difficulty of wiring, the point of connection must be close to the depot. Archer’s office was not more than three hundred yards away, while his house, The Elms, was over a mile. The chances were therefore in favor of the former.

It followed that he must begin by searching Archer’s office for the other receiver, and he turned his attention to the problem of how this could best be done.

And first, as to the lie of the offices. He called at the Electric Generating Station, and having introduced himself confidentially to the manager in his official capacity, asked to see the man whose business it was to inspect the lights of the distillery. From him he had no difficulty in obtaining a rough plan of the place.

It appeared that the offices were on the first floor, fronting along the line, Archer’s private office occupying the end of the suite and the corner of the building nearest to the syndicate’s wharf, and therefore to Ferriby. The supervisor believed that it had two windows looking to the front and side respectively, but was not sure.

That afternoon Inspector Willis returned to the distillery, and secreting himself in the same hiding place as before, watched until the staff had left the building. Then strolling casually along the lane, he observed that the two telephone wires which approached across the fields led to the third window from the Ferriby end of the first floor row.

“That’ll be the main office,” he said to himself, “but there will probably be an extension to Archer’s own room. Now I wonder—”

He looked about him. The hedge bounding the river side of the lane ran up to the corner of the building. After another hasty glance round Willis squeezed through and from immediately below scrutinized the side window of the managing director’s room. And then he saw something which made him chuckle with pleasure.

Within a few inches of the architrave of the window there was a down-spout, and from the top of the window to the spout he saw stretching what looked like a double cord. It was painted the same color as the walls, and had he not been looking out specially he would not have seen it. A moment’s glance at the foot of the spout showed him his surmise was correct. Pushed in behind it and normally concealed by it were two insulated wires, which ran down the wall from the window and disappeared into the ground with the spout.

“Got it first shot,” thought the inspector delightedly, as he moved away so as not to attract the attention of any chance onlooker.