card-marking are as numerous as they are ingenious. They vary from a mark which covers the greater portion of the back of the card to a mark which is invisible. This latter may not appear to be of much utility, but it must be borne in mind the sharp is not restricted to the use of the sense of sight only. Sometimes, indeed, it is necessary for him to know the cards without looking at them, and then a visible mark would be of no possible use to him.

So numerous, indeed, are the systems of marking—almost every card-sharper, worthy of the name, having a system peculiar to himself—that it is impossible to give a tenth part of them. To attempt to do so would be to weary the reader, and, further, it is unnecessary. All these various systems are capable of general classification, and a few leading instances will suffice to give the key to the whole. For brevity and convenience, then, we will consider the subject under the following heads:—