d the alteration of the
adjustment of a shelf is thereby rendered an extremely troublesome
operation. The patent fittings remedy this, and save both time and
trouble; in place of the rows of holes so far apart, metal strips
perforated at intervals of three-quarters of an inch for the reception
of the very simple but strong metal plates, which take the place of the
old studs, are mortised in and screwed to the frames. The insertion, at
the required intervals, of the plates into the perforations in these
strips is made instantaneously, consequently the position of a shelf can
be easily altered without an irritating expense of trouble, and waste of
time. The thinness of the plates renders any mortising in the shelf
unnecessary, and the small intervals between the perforations in the
strips enables the whole space occupied by the shelves to be used most
economically. These fittings, when used with a shelf sufficiently strong
itself to bear the weight, will support without strain more than half a
ton.

[43] _Nineteenth Century_, March, 1890.

[44] Edwards, _Memoirs of Libraries_, ii., 736.

[45] THE SIZES OF BOOKS.--The Associated Librarians of Great Britain
decided upon a uniform and arbitrary scale for the measurement and
description of the sizes of books. In consequence of the many and varied
sizes of papers now manufactured, the terms folio, quarto or 4to.,
octavo or 8vo., twelvemo or 12mo., and so on, as indicating the number
of folds in the printed sheets, can no longer be relied upon as a
definite guide to the sizes of books, hence the change, as follows:--

Large folio la. fol. over 18 inches.
Folio fol. below 18 "
Small folio sm. fol. " 13 "
Large octavo la. 8vo. " 11 "
Octavo 8vo. " 9 "
Small octavo sm. 8vo. " 8 "
Duodecimo 12mo. " 8 "
Decimo octavo 18mo. is 6 "
Minimo mo. below 6 "
Large quarto la. 4to. " 15 "
Quarto 4to. " 11 "
Small quarto sm. 4to. " 8 "

[46] Edwards, _Memoirs of Libraries_, ii., 739.

[47] Blades, _Enemies of Books_.

[48] Edwards, ii., 737.

[49] See p. 106.

_Miscellaneous Appliances._

Whether the library be considered as a workshop or a morning-room, there
are certain necessa