The Open Book page image presentation framework is not designed to
replace printed books. Rather, it is a free, browsable, nonproprietary,
fully and deeply searchable version of the publication which we can
inexpensively and quickly produce to make the material available
worldwide.
For most effective printing, use the "printable PDF page" link available
on each OpenBook page's tool block. The 300 x 150 dpi PDF
linked to it is printable on your local printer.
Copyright 1994, the National Academies Press.
Please use the content on the page image as the authoritative version. HTML may have misrepresentations or apparent omissions.
Page display interface copyright 1999 and 2003, the National Academies Press.