Nor was there any smooth surface within the empty trunks upon which finger impressions might have been left. They were lined with canvas, fine as to quality, but still too rough to carry prints.

Inspector French felt more puzzled and baffled than ever. What, under the sun, were the blankets for? And where was the woman who had carried them about?

He was certainly no further on as to finding her, whether she had crossed to France, or travelled to some other point on the Southern system, or had simply walked out of the station and been swallowed up in the wilderness of London, she was just as completely lost to him as ever. Hard luck that so unexpected a lift as the finding of the trunks should have led to so little.

But there was one thing it had led to. It settled the question of the impersonation. On no other hypothesis could the abandonment of the trunks be explained.

A point of which he had already thought recurred to him. If the unknown had impersonated Mrs. Root she either knew her or knew a great deal about her. The chances, therefore, were that Mrs. Root knew the unknown. It also seemed pretty certain that Mrs. X, as he began to call the unknown in his mind, had really crossed in the Olympic. How else would she obtain the labels and the dinner menu? Granted these two probabilities, it almost certainly followed that the real Mrs. Root and Mrs. X had met on board. If so, would it not be worth while interviewing Mrs. Root in the hope that she might by the method of elimination suggest the names of one or more persons who might have carried out the trick, and thus provide French with another point of attack.

Thinking it would be worth while to investigate the matter, he returned to the Yard and sent a cable to the Pittsburg police asking them to obtain Mrs. Root’s present address.

He glanced at his watch. It was not yet five o’clock, and he saw that he would have time to make another call before going off duty. Fifteen minutes later he pushed open the door of Dashford’s Inquiry Agency in Suffolk Street, off the Strand.

“Mr. Parker in?” he demanded of the bright young lady who came to the counter, continuing in response to her request for his name, “Inspector French from the Yard, but Mr. Parker’s an old friend and I’ll just go right in.”

The girl eyed him doubtfully as he passed through the counter, and, crossing the office, tapped at a door in the farther wall. Without waiting for a reply, he pushed the door open and passed within, shutting it behind him.

Writing at a desk in the centre of the room was an enormously stout man. He did not look up, but grunted impatiently “Well?”