“You see, there are three methods of cheating: the first by hidden cards, the second by marked cards, the third simply by sleight of hand, this being generally used in connection with marked cards. These tricks require great skill and extreme delicacy of touch, for the marks, which are generally at the edge of the cards, are so slight as to be altogether imperceptible save to a trained hand. There are also marks on the back of the cards; these are done in the printing, and are so slight that, unless attention were attracted to them, no one would dream of their existence.” In the course of a week's practice Mark learned where to look for cheating; he could not indeed follow the fingers of his instructor, for even when he knew what was going to be done, the movements were so rapid that his eye could not follow them, and in nine cases out of ten he was unable to say whether the coup had been accomplished or not; but he could see that there was a slight movement of the fingers that could only mean that something was being done. “It would be a good thing,” he said one day, “if every young fellow before going out into the world were to have a course of such instruction as you are giving me; he would learn, at least, the absolute folly of sitting down to play cards with strangers. He would see that he could be robbed in fifty different ways, and would be at the absolute mercy of any sharper. I never had any inclination for gambling, but if I had been inclined that way you would have cured me of the passion for life.” The week's instruction was lengthened to a fortnight, and at the end of that time Mark went to Dick Chetwynd. “Do you know, Dick,” he said, “a gambling place in Buckingham Street?” “I know that there is a hell there, Mark, but I have never been in it. Why do you ask?” “I have rather a fancy to go there,” he replied. “I hear that, although a good many men of fashion haunt the place, the crowd is rather a mixed one.” “It has a bad name, Mark; I have heard some queer reports about it.” “Yes, so have I. I should think that it is a very likely place for a man like Bastow to go to if he has any liking for play. Of course he would get up as a gentleman. At any rate, I have been making what inquiries I can in some of the thieves' quarters, and have come to the conclusion that he is not likely to have taken up his abode there, and I don't think I can do better than make a round of some of these doubtful houses. I should like to begin with this, and then work downwards.”