On Calls and Calling

"Call when you're called upon is a safe guide for the newcomer or the newly married. In fact, it is a very hard-and-fast rule, and although it may seem hard when you are in a strange place and know nobody, you must wait until the older residents call upon you before you may visit them, or make a move toward getting to know them.
But once anyone has called, make a point of returning the call within ten days, or a fortnight at the very most. Four o'clock is a very good time for paying a call, although any time between 3:30 and 5:30 is permissable. No calls of any kind should be made earlier or later than this. Before you go, put ready in your card case just the card you'll need, so that you can slip them out easily at the end of your call."