SCIENCE 
IS 
KNOWLEDGE, 
KNOWLEDGE 
IS 
POWER. 
A PRACTICAL JOURNAL OF 
HOME ARTS 
Vol. IV 
NEW YOEK, OCTOBER, 1881. 
No. 10. 
Sizes of Books. 
U R young readers 
have doubtless been 
often puzzled to 
know what was 
meant by the terms 
12 mo., 8vo., etc., 
used in describing 
the sizes of books, 
and as we have fre- 
quently been asked 
to explain these 
terms, we will try 
and make the subject plain. 
When a publisher undertakes to put the 
intellectual labors of an author into the 
form of a book, one of the first things to 
be decided is the size of the page, and this 
generally depends upon the amount of 
reading matter in the work, though some- 
times it is governed by the size of the 
illustrations or engravings, if there are 
any. At first sight this would look as if 
the book were made for the engravings, 
and not the engravings for the book; but 
if the reader will think again he will see 
that in order to show clearly what is in- 
tended to be illustrated, the engravings 
must have a certain size. If too small^ 
some of the important parts would be 
visible only by the use of a magnifier. 
The price at which the book is to be 
sold has also an important influence on 
the size. If the book is to be a handsome 
holiday volume, the size of the page will 
probably be larger than if the work is in- 
tended for ordinary buyers. This is par- 
ticularly the case in regard to scientific 
and industrial books, where great econ- 
omy is often desirable. 
Having decided upon the size that the 
page ought to be, the next questions are 
as to the size of paper and the number of 
times it shall be folded to give the desired 
page. At first all paper was of the same 
size, and a sheet when folded once gave 
four pages, which were of the size known 
as folio. Folded again, there were eight 
pages, and the size was called quarto. 
But eight pages make four leaves ; henee 
quarto (or 4to.) expresses the number of 
leai^es to the sheet, and not the number of 
pages. Folded again, the sheet gives us 
eight leaves or sixteen pages, and is 
called an octavo, which, when written, is 
