=Bibliographies.=--Bibliographic references by footnotes serve in most books. Bibliographies of greater extent should be arranged alphabetically at the end of each chapter of the book, or numbered serially and referred to by numbers in the text. The custom is to print the titles of books in roman and the titles of periodicals in italics. Abbreviations should conform to the well-established style sheets of technical societies. We recommend particularly the abbreviations of:
{ Issued by the American Society of ENGINEERING INDEX { Mechanical Engineers, 29 West 39th { Street, New York.
{ Issued by the American Chemical CHEMICAL ABSTRACTS { Society, 1709 G Street, N. W., { Washington, D. C.
{ Issued by the Board of Control of { Botanical Abstracts, Dr. Donald BOTANICAL ABSTRACTS { Reddick, Business Manager, Cornell { University, Ithaca, N. Y.
{ Issued by the Zoological Society of THE ZOOLOGICAL RECORD { London, Regent's Park, London.
THE INTERNATIONAL CATALOGUE { Issued by the Royal Society of OF SCIENTIFIC LITERATURE { London.
The extent of the bibliography will vary, of course, with the nature of the subject and the treatment. The tendency to-day appears to be toward rather excessive bibliographies, which do not seem to us generally to be justified. For a simple rule, we recommend "bibliographies of easily accessible sources."
=Tables of Contents.=--Detailed tables of contents to run in the front of the book serve a useful purpose. They should, however, be kept down to reasonable limits.
There are three forms of contents used in our books:
(1) A simple list of chapter headings. In many cases this is sufficient.
(2) Chapter headings with all articles or sub-headings given underneath. These may either be listed or "run in." With a good index, such a full table of contents seems hardly to serve a useful purpose.
(3) The chapter headings with the outstanding sub-headings listed or "run in" underneath. When these headings are selected carefully they give a quick but comprehensive picture of the contents.
Lists of illustrations are nowadays generally regarded as unnecessary in a technical book, and should be prepared only for the guidance of the author and the publisher.
=Indexes.=--A good subject index is necessary in all technical works. A widely-read periodical in New York at one time published regularly the following notice of subject books which were submitted to it for review and found to be without indexes: