the stack system is that it is unsuitable for libraries where the readers are allowed to have access to the shelves, its principle being the warehousing of the books in the most compact manner, and not the provision of facilities for reading them. In the Amherst College Library this difficulty has been met by shortening the alternate stacks to a height at which they can be used as tables. But even this will only give accommodation for a very small number of readers; and if the general public are to be admitted to the shelves, some modification of Dr. Poole's plan seems likely to be the best. The loss of space is a serious objection to allowing the public access to the shelves at all; and the multiplication of reading-rooms is objectionable, as necessitating a similar multiplication of catalogues and books of reference.
To calculate how many books can be shelved in a bookcase, it is usual to allow 10 volumes to each foot of shelving for ordinary octavos, and 6 for folios and quartos. The average over the whole shelving of an ordinary collection of books will probably be 8½ volumes to the foot. If it is wanted to know how many books a room will hold if fitted with cases 7 feet 6 inches high, the method of calculation is a little different. Let us suppose that the case is 16 inches deep, and has books on each side; that the width of passageway between it and the next case is the minimum of 32 inches; and that each shelf is 36 inches in length. The floor space that one division of one side of the case will take is half the width of the
