If you wish to get the “full capacity,” as it is reported in many plans, make your volume-multiplier ten instead of eight, or add twenty-five per cent to your first calculation, which amounts to the same thing. But eight to the foot is practically full capacity for closely classified libraries, where frequent gaps must be left for growth, at the end of each subject.
Sliding Cases
We can wisely borrow from England the “sliding presses” which Dr. Richard Garnett brought to the attention of the Library Association of the United Kingdom at its annual meeting of 1891, having previously described them in Dewey’s Library Notes and elsewhere in 1887.
Adapted from the Bethnal Green library in 1886, they were put on trial in the British Museum in 1887, and have since been in operation, regarded apparently as an invention quite as valuable as the stack appears to us. “I think enough has been said,” to quote Dr. Garnett’s words, “to convince librarians of the expediency of taking the sliding-press, or some analogous contrivance, into account in plans for the enlargement of old libraries, or the construction of new ones.”
The British Museum press is described as “an additional bookcase hung in the air from beams or rods projecting in front of the bookcase it is desired to enlarge, working by rollers running on metal ribs, and so suspended as not to touch the ground anywhere.” In other words, it is a movable bookcase parallel to a fixed case, and sliding to and from it by wheels above. It may be distinctively called a hanging case or press. It is better suited to the arrangement of aisles and construction of floors in the British Museum than to most American libraries, and so far as I know has not been copied here.
[See illustration in Library Notes,[302] and also in Burgoyne.[303]]
Another double press used at the Museum is called by Dr. Garnett the pivot press. It is apparently a second case, kept front to front close to the fixed case and swung out from it when wanted, by a door-motion hinged on a perpendicular pivot; overhung, I gather, at the Museum, but elsewhere running by wheels on metal semi-circular tracks laid on or in the floor. Such were early experiments in Trinity College, Dublin, twenty-five years ago. These might be called folding bookcases. They have not yet been copied in America.
A third kind of movable bookcase, which may more properly be called the sliding case, is used in the Patent Office Library, London. This apparently also swings from the top. Duff-Brown[304] describes it: “These presses are swung closely side by side, and drawn out, one at a time, as required.” He does not say drawn out endwise, however.