itself can tell; but for five hundred years the book has never been in
such unstable equilibrium as at present; the proverb "A book's a book"
has never possessed so little definite meaning. This condition applies
chiefly to the paper, but as this changes, the binding will also change
from its present costly and impermanent character to something at once
cheaper and more durable.

The changes in modern paper have worked in two opposite directions,
represented on the one hand by Oxford India paper, with its miraculous
thinness, opacity, and lightness, and on the other hand by papers that,
while also remarkably light, offer, as a sample book expresses it,
"excellent bulk"; for instance, 272 pages to an inch as against 1500 to
an inch of Oxford India paper.[3] The contrasted effects of these two
types of material upon the book as a mechanical product are well worth
the consideration of all who are engaged in the making of books.

Some of these results are surprising. What, for instance, could be more
illogical than to make a book any thicker than strength and convenience
require? Yet one has only to step out into the markets where books and
buyers meet to find a real demand for this excess of bulk. Though
illogical, the demand for size in books is profoundly psychological and
goes back to the most primitive instincts of human nature. The first of
all organs in biological development, the stomach, will not do its work
properly unless it has quantity as well as quality to deal with. So the
eye has established a certain sense of relationship between size and
value, and every publisher knows that in printing from given plates he
can get twice as much for the book at a trifling excess of cost if he
uses thicker paper and gives wider margins. That all publishers do not
follow these lines is due to the fact that other elements enter into the
total field of bookselling besides quantity, the chief of which is cost,
and another of which, growing in importance, is compactness. But it is
safe to say that to the buyer who is not, for the moment at least,
counting the cost, mere bulk makes as great an appeal as any single
element of attractiveness in the sum total of a book.

This attraction of bulk receives a striking increase if it is associated
with lightness. The customer who takes up a large book and suddenly
finds it light to hold receives a pleasurable shock which goes far
towards making him a purchaser. He seems not to ask or