This is a mark put on the cards during the progress of the game, with finger nail or thumb nail. It is put on so that the gambler may know just what his opponent holds. The ace is marked with a straight line or mark in upper right hand corner. The king, is a straight line about one-half inch long in the center of the card. The queen is a straight line a half inch longer than the king. The jack is a straight line about the center of the card. The ten spot is designated by a straight line or mark in the same position as the ace. The nine spot is a slanting line in position of king. The eight is a slanting line in position of queen. Seven is a slanting line in position of jack. The six is denoted by a straight line in position of ace, running across the card at right angles to the ace mark. The five is same as six in position of king. The four is the same as five and six in position of queen. The tray is same mark in position of jack. Deuce is a cross below the jack sign. The mark denoting the suit of the card is placed in the center of the top of the card. Hearts are designated by a perpendicular line at the center end of the card. Clubs are shown by a horizontal line in the same position. Diamonds are shown by a slanting line in the same position. And of course, as hearts, clubs and diamonds are marked, a card without a mark would be a spade. This is one of the most dangerous tricks, as it is done during the progress of the game, and unless some one knows something about it, it would never be detected. THE DOUBLE DISCARD. This is used by many of the gamblers, and is done through the neglect of the players. The man doing this will always draw three cards, no matter what he may hold in his hand. It is done by placing the cards he wishes to keep on top of the ones he wishes to discard, and laying them down beside him, ostensibly discarding them. As he is given his three cards he looks them over and has eight cards out of which to pick his hand. Suppose in his original hand he held three diamonds and a club; he places the three diamonds beside him and calls for three cards, holding one diamond and the club in his hand. When his cards are dealt him he has five cards out of which to pick two diamonds. He selects two cards and discards three cards; at the same time he picks up the three cards that he discarded first. Very few are expert enough to this trick without detection. CHECK SIGNS.