where space is of the greatest value. Passages 3 feet wide will in practice be found quite narrow enough. The central gangway running across the room between the ends of the cases must be wide enough to take the staircase which leads from one book storey to the next, and for a few narrow tables for standing books requiring replacement, &c. The staircase should be in straight flights and not circular, with a width of at least 4 feet. There should be a small lift for books placed near the door, and running from top to bottom of the room, so that books may be easily and readily transferred from one storey to another. If the book stores are very large and some distance from the readers, endless bands running over rollers or cable lines can be fitted along the gangways, to carry the books from the attendants in the book stores to the delivery desk. Examples of book railways of this kind may be seen in the new library of Congress at Washington (Fig. 45), and in the public library, Boston (Fig. 115).
The late Dr. Poole of the Chicago Library, while agreeing with this principle of shelving books, strongly objected to the stacks being more than one storey in height. His plan for constructing a large library was described in detail in a "Circular of Information" issued by the United States Bureau of Education in 1881, in which he said—
"My first requirement is a lot of ground 200 feet square, surrounded on all sides by streets, or, what is better, by other open space. On the middle of the side most appropriate for the main
