=170.= Every library should buy more chairs than are required. This will enable the chairs to be removed for cleaning purposes in batches of a dozen or more, their places being taken by the spare ones. This will prevent the seating accommodation from being reduced during any cleaning operations. =171. Desks.=--For staff purposes ordinary school desks will be found ample. These are provided with side flaps and a locking compartment. A Canadian form with shelves and a lock-up desk flap, with pigeon holes, suitable for going against a wall, is a useful type of desk for assistants doing a special class of work, as the desk flap can be locked back out of the way, and so protect the papers or work. [Illustration: FIG. 55.--Chair with Hat Rail and Umbrella Holder (Section 169).] [Illustration: FIG. 56.--Chair with Folding Tray or Shelf (Section 169).] =172.= For large libraries, where an elevated superintendent’s desk is necessary, the combined desk and drawer cabinet used in the Mitchell Library, Glasgow, has many advantages. =173. Lecture Room.=--Furniture and fittings for children’s departments and lecture rooms require special consideration. The former are dealt with in Division XIII. In the lecture room the principal fittings are the platform and the fittings connected with the use of the lantern. Platforms should be wide, and should be as long as it is possible to make them having regard to economy of space in the room. A height of three feet is suitable, and the structure should be solid, so that it may not echo or squeak beneath the tread, and a covering of some sound-deadening material--thick cork-lino or cocoanut-matting--is desirable. A counter or fixed table running along the front has been found useful, and to this water, gas, and similar fittings may be connected for use in science lectures; but this counter is not usually required, and it may obstruct the screen and will certainly prevent the use of the platform for dramatic and similar representations for which a clear stage is necessary. Green baize hangings as a background and front curtains of this material are very effective for several purposes. The platform should so be placed that it can be reached by the lecturers without the necessity of passing through the audience.