[click on pictures to enlarge - taken via iPhone]
"This is Best Society’s favorite form of invitation. It is used on nearly every occasion whether there is to be music or a distinguished visitor, or whether a hostess has merely an inclination to see her friends. She writes on her personal visiting card: “Do come in on Friday for a cup of tea and hear Ellwin play, or Farrish sing, or to meet Senator West, or Lady X.” Or even more informally: “I have not seen you for so long.”
[...] If the tea is of any size, from twenty upwards, the table is set in the dining-room and two intimate friends of the hostess “pour” tea at one end, and chocolate at the other. The ladies who “pour” are always especially invited beforehand and always wear afternoon dresses, with hats, of course, as distinguished from the street clothes of other guests. As soon as a hostess decides to give a tea, she selects two friends for this duty who are, in her opinion, decorative in appearance and also who (this is very important) can be counted on for gracious manners to everyone and under all circumstances." - Teas and Other Afternoon Parties, Emily Post (1873–1960). Etiquette. 1922.
So there you have it, pictures of an afternoon tea at The Rotunda at The Pierre with two friends of mine, positively decorative in appearance and displaying gracious manners under all circumstances.