nt.

A book that consists entirely of plates or single leaves must be made
up into sections with guards, and sewn as usual. In books in which
there are a great many plates, it is often found that two plates
either come together in the centre of a section, or come at opposite
sides of the same pair of leaves. Such plates should be guarded
together and treated as folded sheets (see fig. 13).

[Illustration: FIG. 13.]

In order to be sure that the pages of a book to be guarded throughout
will come in their proper order, it is well to make a plan of the
sections as follows, and to check each pair of leaves by it, as they
are guarded:--

Thus, if the book is to be made up into sections of eight leaves, the
pairs of leaves to be guarded together can be seen at once if the
number of the pages are written out--

1, 3, 5, 7,--9, 11, 13, 15.

First the inside pair, 7 and 9, are guarded together with the guard
outside, then the next pair, 5 and 11, then 3 and 13, and then the
outside pair, 1 and 15, which should have the guard outside. A plan
for the whole book would be more conveniently written thus--

1-15 17-31 33-47
3-13 19-29 35-45
5-11 21-27 37-43
7-9 23-25 39-41, and so on.

To arrange a book of single leaves for guarding, it is convenient to
take as many leaves as you intend to go to a section, and opening them
in the centre, take a pair at a time as they come.

The number of leaves it is advisable to put into a section will depend
on the thickness of the paper and the size and thickness of the book.
If the paper is thick, and the backs of the leaves have been pared,
four leaves to a section will be found to answer. But if the paper is
thin, and does not allow of much paring, it is better to have a larger
section, in order to have as little thread in the back as possible.

The sheets of any guarded book should be pressed before sewing, in
order to reduce the swelling of the back caused by the guards.

THROWING OUT

[Illustration: FIG. 14.]

Maps or diagrams that are frequently referred to in the text of a
book, should be "thrown out" on a guard as wide as the sheet of the
book. Such maps, &c., should be placed at the end, so that they may
lie open for reference while the book is being read (see fig. 14).
Large folded maps or diagrams should be mounted on linen. To do this
take a piece of jaconet and pin it out flat on the board, t