Keep silence sometimes, upon subjects which you are known to be a judge of. So your silence, where you are ignorant, will not discover you.
To use phrases which admit of a double meaning is ungentlemanly, and, if addressed to a lady, they become positively insulting.
There is a vulgar custom, too prevalent, of calling almost everybody "colonel" in this country, of which it is sufficient to say, that this false use of titles prevails most among the lower ranks of society—a fact which sufficiently stamps upon it its real character, and renders it, to say the least, a doubtful compliment to him who has no right to the title.
Think like the wise; but talk like ordinary people. Never go out of the common road, but for somewhat.
Don't dispute against facts well established, merely because there is somewhat unaccountable in them. That the world should be created of nothing is to us inconceivable but not therefore to be doubted.
As you are going to a party of mirth, think of the hazard you run of misbehaving. While you are engaged, do not wholly forget yourself. And after all is over, reflect how you have behaved. If well, be thankful; it is more than you could have promised. If otherwise, be more careful for the future.
It will never do to be ignorant of the names and approximate ages of great composers, especially in large cities, where music is so highly appreciated and so common a theme. It will be decidedly condemnatory if you talk of the new opera "Don Giovanni," or Rossini's "Trovatore," or are ignorant who composed "Fidelio," and in what opera occur such common pieces as "Ciascun lo dice," or "Il Segreto." I do not say that these trifles are indispensable, and when a man has better knowledge to offer, especially with genius or "cleverness" to back it, he will not only be pardoned for an ignorance of them, but can even take a high tone, and profess indifference or contempt of them. But, at the same time, such ignorance stamps an ordinary man, and hinders conversation.
Don't talk of "the opera" in the presence of those who are not frequenters of it. They will imagine that you are showing off, or that you are lying, and that you have never been to the opera twice in your life. For the same reason, avoid too frequently speaking of your acquaintance with celebrated men, unless you are a public man yourself, who would be supposed to have such acquaintance.
Do not sit dumb in company. That looks either like pride, cunning, or stupidity. Give your opinion modestly, but freely; hear that of others with candor; and ever endeavor to find out, and to communicate truth.
In mixed company, be readier to hear than to speak, and put people upon talking of what is in their own way. For then you will both oblige them, and be most likely to improve by their conversation.