In all libraries, there should be a receiving or packing room, where boxes and parcels of books are opened and books mended, collated, and prepared for the shelves. This room may well be in a dry and well lighted basement. Two small cloak-rooms for wraps will be needed, one for each sex. Two toilet rooms or lavatories should be provided. A room for the library directors or trustees, and one for the librarian, are essential in libraries of much extent. A janitor's room or sleeping quarters sometimes needs to be provided. A storage room for blanks, stationery, catalogues, etc., will be necessary in libraries of much extent. A periodical room is sometimes provided, distinct from the reading-room or the delivery department. In this case, if several hundred periodicals are taken, an attendant should be always present to serve them to readers, from the shelves or cases where they should be kept in alphabetical order. Without this, and a ticket system to keep track of what are in use, no one can readily find what is needed, nor ascertain whether it is in a reader's hands when sought for. System and the alphabet alone will solve all difficulties. As to the space required for readers in a periodical room, it may be assumed that about five hundred square feet will accommodate twenty-five readers, and the same proportion for a larger number at one time. A room twenty-five by forty would seat fifty readers, while one twenty-five by twenty would accommodate twenty-five readers, with proper space for tables, &c. The files for newspapers are referred to in another chapter on periodicals. In a library building, the heating and ventilation are of prime importance. Upon their proper regulation largely depends the health and consequently the efficiency of all employed, as well as the comfort of the reading public. There is no space to enter upon specific descriptions, for which the many conflicting systems, with experience of their practical working, should be examined. Suffice it to say in general, that a temperature not far below nor above 70 degrees Fahrenheit should be aimed at; that the furnace, with its attendant nuisances of noise, dust, and odors, should be outside the library building--not under it; and that electric lighting alone should be used, gas being highly injurious to the welfare of books.