The Ladies' Book of Etiquette, and Manual of Politeness

You will be guilty of a great breach of politeness, if you answer either a note or letter upon the half sheet of the paper sent by your correspondent, even though it may be left blank. Never write, even the shortest note, in pencil. It looks careless, and is rude. Never write a letter carelessly. It may be addressed to your most intimate friend, or your nearest relative, but you can never be sure that the eye for which it is intended, will be the only one that sees it. I do not mean by this, that the epistle should be in a formal, studied style, but that it must be correct in its grammatical construction, properly punctuated, with every word spelt according to rule. Even in the most familiar epistles, observe the proper rules for composition; you would not in conversing, even with your own family, use incorrect grammar, or impertinent language; therefore avoid saying upon paper what you would not say with your tongue. Notes written in the third person, must be continued throughout in the same person; they are frequently very mysterious from the confusion of pronouns, yet it is a style of correspondence much used and very proper upon many occasions. For compliment, inquiry where there is no intimacy between the parties, from superiors to inferiors, the form is elegant and proper. If you receive a note written in the third person, reply in the same form, but do not reply thus to a more familiar note or letter, as it is insulting, and implies offence taken. If you wish to repel undue familiarity or impertinence in your correspondent, then reply to the epistle in the most formal language, and in the third person.