The salutation, says a French writer, is the touchstone of good breeding. According to circumstances, it should be respectful, cordial, civil, affectionate or familiar: an inclination of the head, a gesture with the hand, the touching or doffing of the hat.
If you remove your hat you need not at the same time bend the dorsal vertebr' of your body, unless you wish to be very reverential, as in saluting a bishop.
If an individual of the lowest rank or without any rank at all, takes off his hat to you, you should do the same in return. A bow, says La Fontaine, is a note drawn at sight. If you acknowledge it, you must pay the full amount. The two best-bred men in England, Charles the Second and George the Fourth never failed to take off their hats to the meanest of their subjects.
If you have anything to say to anyone in the street however intimate you may be, do not stop the person, but turn round and walk in company; you can take leave at the end of the street.
If there is any one of your acquaintance, with whom you have a difference, do not avoid looking at him, unless from the nature of things the quarrel is necessarily for life. It is almost always better to bow with cold civility, though without speaking.
Good sense and convenience are the foundations of good breeding; and it is assuredly vastly more reasonable and more agreeable to enjoy a passing gratification, when no sequent evil is to be apprehended, than to be rendered uncomfortable by an ill-founded pride. It is therefore better to carry on an easy and civil conversation. A snuff-box, or some polite accommodation rendered, may serve for an opening. Talk only about generalities, the play, the roads, the weather. Avoid speaking of persons or politics, for, if the individual is of the opposite party to yourself, you will be engaged in a controversy: if he holds the same opinions, you will be overwhelmed with a flood of vulgar intelligence, which may soil your mind. Be reservedly civil while the colloquy lasts, and let the acquaintance cease with the occasion.