=155. Racks for Filing.=--Wooden racks or iron-pipe racks may be used for a variety of purposes, such as storing unbound newspapers and periodicals, pamphlets, and all kinds of loose papers or bundles. Such racks are best made in a light, open form, so as to reduce the collection of dust to a minimum, while admitting air and light freely. =156. Galleries.=--Galleries of iron are sometimes added to reference libraries and in other departments to provide a means of reaching high wall-shelves, and also to give additional accommodation for storage. They are a feature of the large stack rooms of American libraries, wherein the books are all massed together, gallery above gallery and tier above tier. Unless there is some very strong reason, architectural or otherwise, galleries should be avoided in every public library where rapid service of readers is necessary. Save for storing little-used stock, galleries are not recommended in any situation, unless the pressure for book space is very great. When galleries must be provided, care should be taken to provide adequate approaches. If a straight staircase is out of the question, a circular iron one should be provided, wide enough to enable an assistant to go up or down comfortably with an armful of books. In some libraries the circular iron staircases are more like exaggerated corkscrews than proper means of getting up and down from a gallery or floor. It is much better to have stairways in a single flight, which will allow of two persons passing each other, and for this purpose they ought to be at least three feet wide. In libraries with bookcases of the uniform height of seven feet six inches, long ladders will be unnecessary, but in cases where they must be used, step ladders are preferable to rung ones. A light form of step ladder which is used in many public libraries and shops is illustrated (Fig. 38). For all practical purposes this ladder will be found ample. [Illustration: FIG. 38.--Lattice-work Steps (Section 156).] [Illustration: FIG. 39.--Short Steps for Low Shelves (Section 156).] Short steps for enabling the upper shelves of seven foot six inch cases to be scanned easily are made in various forms, some being folding and others fixed. The variety as illustrated (Fig. 39) will be found useful. [Illustration: FIG. 40.--Continuous Wooden Step and Handles, Hornsey Central Library (Section 157).]