Sergeant Paul Prout was beginning to come to the conclusion that the Corner House mystery would have to be relegated to the long list of crimes concerning which Scotland-yard is fain to be silent. At any rate, the matter was utterly beyond him. Given a clue to work on, no man in the force could display more tenacity and skill. But there was nothing to go upon, and Prout was utterly devoid of imagination.

Of course, there was always the chance of coming on the track obliquely. None knew better than Prout how frequently one crime interlocked with another, and how often in looking for one particular criminal another had been arrested.

He came into the inspector\'s office in answer to a summons. Inspector Manton passed over some papers to his subordinate.

"I want you to read them and act upon them," he said. "You\'ll have to put that Corner House business out of your head for a day or two at any rate. It appears that a gang of cosmopolitan swindlers have established their headquarters somewhere in Soho, and by means of using several addresses they are getting a tremendous quantity of goods which they proceed to turn into money. Here is one of their advertisements cut from the Standard. You had better answer it, and get in touch with the fellows that way. But nobody can manage that sort of thing better than you."

Prout felt himself quite capable to account for this matter. He proceeded to lay the whole particulars before a friend in the wholesale silver-plate line--just the kind of article the gang of thieves affected--and so procured the genuine address of a genuine trader for the purposes of the capture.

"I expect you\'ll get orders from five or six addresses," said Prout. "If so, send the stuff on, not too much at a time, and ask for references. You\'ll get the reference, of course; in other words, Jones and Company, of Gray\'s Inn, will recommend Smith and Company, of Market Street. When you get all the references in let me know, because by that means I shall be in possession of every address used by these fellows."

To keep the big swindle going on and to avoid awkward mistakes it was necessary for the confederates to meet at intervals. By small purchases at one address or another Prout had pretty well got to know all the gang by sight, and by following one or another he discovered at last where the rendezvous was--a public-house of not too good repute in White Lane, leading off Oxford Street.

Next day a sallow, seedy, broken-down shop assistant sought and obtained a bedroom at the Orange Tree public-house. He seemed to have money, and therefore he was welcome. He hinted that he was "in trouble" over some stolen goods from his late employer\'s shop, and the Orange Tree received him with open arms.

It was weary work sitting there and pretending to drink, but patience has its reward at last. Gradually the shy swindlers became accustomed to the seedy shop assistant, who even went out of his way to give them hints as to credulous firms. It seemed to Prout that he knew all the gang at last save one.

And this one he particularly wanted to see, because the name was unknown to him. In all the swindlers in London it was the first time Prout had heard of one called "Frenchy." And the particular member of the gang--absent from London on business--seemed to be the leader of them all. Once Frenchy showed himself, Prout would give the sign, and within an hour the gang would be laid by the heels.

He came at length, a little dapper man, with a slight hump ............