'Masters, Brainerd,' our chief said to us one morning, 'they are going to want a lot of good men at that World's Fair; I think I'd better put you both on the list.' And this was all that was said then, but when we were out of his presence Dave exploded.

'Wants to send us to watch little boys, look after ladies' kerchiefs, and hunt up lost babies, does he?' he began, in a fume. 'It's not meself that'll do it; d'ye hear, Masters? I'll go like the biggest gentleman of all, or like the sleuth I am, but no child-rescuing and kid-copping for me! Let his honour give us,' with a theatrical gesture, 'a foeman worthy of our steel.'

Nothing came of this whimsical tirade, and a week had passed before the chief spoke again upon the subject. Then we were both called into his private office, and he said:

'Boys, we have just found out to a certainty that Greenback Bob and his pals are going to operate at the World's Fair. I've already promised them more good men than I like to spare, but we can't let Bob and his crowd slip. I did not really mean to send you, either of you, with the others; but this is something worth while.'

'I should say!' broke in Dave, who was no respecter of persons, unless perhaps it might have been of Dave Brainerd. 'Do you mean to tell us, Cap, that the dandy Frenchman is in it?'

'He is very much in it. He crossed from Calais on the last boat in hot haste, and I'm much mistaken if the whole gang is not already on its way to the White City, though he only reached this side the night before last; and there's another party who may give us some trouble. We don't know him, but he is said to be an all-round bad one, just come over from Calais with this Delbras. I wish I could give you even a description of him.'

Greenback Bob was a counterfeiter, or so it was believed, for he was so bold, so shrewd, and so generally successful, that no one as yet had been able to entangle him in the meshes of the law; though samples of what was believed to be his handiwork had been passed from hand to hand, and travelled far before they had been challenged, and their journeys summarily ended in the cabinet of our chief. Bob was known as a gambler, too, and more than once had he been watched and shadowed because of some ill deed connected with his name; we had seen his face, and his picture adorned the rogues' gallery. Delbras, however, was likely to give us some trouble; we had seen him, it is true, but it was only a fleeting glimpse, with the possibility that he was at the moment cleverly disguised.

Of Delbras we knew, first, that he was and had been for years the occasional partner or confederate of the counterfeiter, and presumably a counterfeiter also; next, that he was set down in the records of the London police as 'dangerous'; and last, that he had crossed the ocean, leaving Paris, which had grown 'too hot to hold him,' and was avowedly en route for the World's Fair, it was thought upon mischief intent.

This last item came to our chief direct from the French police, together with the information that two or three diamond robberies which had occurred in the French capital during the previous winter were laid at his door, although it had been thus far impossible to bring the thefts home to him.

Concerning Greenback Bob—the fellow was known to us by no other name—we felt quite sanguine; we had seen him, we had his photograph and his full description according to the Bertillon system, and, once seen, he would hardly be lost to sight again, or so we flattered ourselves. Delbras we must identify through Bob, or as we best could; and the third member of the 'gang'—well, a great deal must be left to chance, as usual.