Extracts from 19th century ballroom manuals:
From a New York publication 1864:
"Loud conversation, profanity, stamping the feet, writing on the wall, smoking tobacco, spitting or throwing anything on the floor, are strictly forbidden."
"The practice of chewing tobacco and spitting on the floor, is not only nauseous to ladies, but is injurious to their dresses."
"A gentleman should not address a lady unless he has been properly introduced."
"No persons engaged in a dance that requires their assistance to complete the set should leave the room or sit down before the dance is finished."
From a Boston publication 1858:
"Persons who have no ear for music, that is to say, a false one, ought to refrain from dancing."
"Married or young ladies cannot leave a ballroom, or any other party, alone. The former should be accompanied by one or two other married ladies, and the latter by their mother, or by a lady to represent her."
"Ladies should avoid talking too much; it will occasion remarks. It has also a bad appearance to whisper continually in the ear of your partner."
"In giving the hand for ladies' chain or any other figures, those dancing should wear a smile, and accompany it with a polite inclination of the head, in the manner of a salutation."
"In public balls, a gentleman offers his partner refreshments, but which she very seldom accepts, unless she is well acquainted with him."
From a Dundee publication 1890:
"Change partners often during the evening, in order that all may enjoy themselves. When requiring to use a handkerchief, put it in your pocket immediately when finished with it. Avoid all vulgar practices, such as biting your nails, making noise with the feet etc."
From a London publication 1817:
"No person during a Country Dance, should hiss, clap, or make any other noise, to interrupt the good order of the company."
"Snapping the fingers, in Country Dancing and Reels, and the sudden howl or yell (introduced in some Scotch parties as partly national with them) ought particularly to be avoided, as partaking too much of the customs of barbarous nations."
"Gentlemen are not allowed to enter the ballroom in boots, spurs, gaiters, trowsers, or with canes or sticks; nor are loose pantaloons considered proper for a Full Dress Ball."
Source for all the above: Scotland through her country dances - George S. Emmerson (London: Johnson Publications, 1967, pp. 23-24). Unfortunately the author does not include detailed references to sources.