This section of the book is from the "Household Companion: The Home Book Of Etiquette" book.
When a dinner is given at a public restaurant, a table can be reserved in the public dining-room, or a private room can be engaged. It is usual to order the dinner beforehand, so that there will be no needless delay in serving it when the guests arrive.
If a lady gives the dinner it is better for the guests to meet at her house, so that they may all go together to the restaurant, but if an unmarried gentleman is the host he must appoint an hour for the party to meet him in the vestibule of the restaurant, and the lady who has consented to chaperon his dinner must be there very punctually, in order to spare any unmarried lady the annoyance of arriving alone at a public place.
The style of the dinner must rest with the taste of the host or hostess, but it should resemble as nearly as possible a dinner in a private house, both in table appointments, variety of dishes, service, etc.
It is perfectly admissible for an unmarried lady to dine at a restaurant, provided that she is properly chaperoned.
Lunches and breakfasts are, under the above circumstances, governed by the same rules as those given in regard to dinners.
Ladies may lunch or breakfast without gentlemen in respectable public restaurants, but two ladies should if possible be together, rather than that one should lunch or breakfast alone.
Of course, no one needs to imagine that in entertaining a few friends at dinner all this ceremony is indispensible. It belongs to occasions where formality and close attention to fixed social rules are considered neccessary, but there is an agreeable form of informal dinner which calls for no manual of observance, in which the friends are taken into the bosom of the family and the ease of unfettered home intercourse prevails. For such dinners there are no set rules; every community, every family, make their own laws, and calmly ignore or simply laugh at the dictates of fashion. Here soup may be omitted, if not cared for; you may pass up your plate to your host for a slice of beef; you may do a dozen things that are quite out of order where formality prevails, and be as heedless and happy as you please. But all this is behind closed doors; when you fall under fashion's eagle eye no such looseness is for a moment to be considered; you must eat and drink to rule and measure or consider yourself a candidate for banishment.