it requires that each person owning and
arranging a library should have a pretty
accurate general knowledge of the sizes of his
books. Secondly, it may be expedient to
introduce here and there, by way of exception,
a single movable shelf; and this, I believe,
will be found to afford a margin sufficient to
meet occasional imperfections in the
computation of sizes. Subject to these remarks, I
have considerable confidence in the
recommendation I have made.

I will now exhibit to my reader the
practical effect of such arrangement, in bringing
great numbers of books within easy reach.
Let each projection be three feet long, twelve
inches deep (ample for two faces of octavos),
and nine feet high, so that the upper shelf
can be reached by the aid of a wooden stool
of two steps not more than twenty inches
high, and portable without the least effort in
a single hand. I will suppose the wall space
available to be eight feet, and the projections,
three in number, with end pieces need only
jut out three feet five, while narrow strips of
bookcase will run up the wall between the
projections. Under these conditions, the
bookcases thus described will carry above
2,000 octavo volumes.