ON THE DUTY OF THE PLAYERS TO EACH OTHER.
1. Each player must look after his own interest, and exercise his own discretion. His opponent cannot be compelled to answer such questions as, “Is the ball outside or inside the string?” “Are the balls in contact?” and so forth. These are questions for the player’s own judgment to decide.
2. When the cue-ball is very near another ball, the player must not play directly upon that ball without having warned his adversary that they do not touch, and given him or his umpire time to be satisfied on that point.
3. It is obligatory upon the adversary or umpire to call “time!” or give some other notice of his approach, if, while the player is preparing to make a stroke, either of them desires to look at the balls, or submit a question to the referee.
4. Each player should attend strictly to his own game, and never interfere with his adversary’s, except in the cases mentioned in [Section 9], on p. 804, or when a foul stroke or some other violation of these rules may call for forfeiture.
ON THE DUTY OF THE MARKER AND THE SPECTATORS TO THE PLAYERS.
1. In a single game, no one, except the player and his umpire, has a right to interfere with the play, or point out an error which either has been or is about to be committed. The player to whose prejudice the foul stroke is being or has been made, should find that out for himself.
2. Even after a stroke has been made, no one in the room has any right to comment upon it, either for praise or blame: for the same stroke may occur again in the course of the game, and the player’s play may be materially altered by the criticism to which he has just been listening.
3. Let the marker and spectators keep their places as much as possible, for if they crowd or move around the table they are liable to interfere with the players, and certain to distract their attention.