76.—When the subject of the book has been clearly ascertained, an entry taken from the book itself or from the principal entry already written, is made under the name of the direct and definite subject of the book, not under the class of literature to which it belongs or even the form in which it is written. It is of the first importance that the cataloguer should definitely decide the particular subject-name he will adopt in order to avoid the somewhat common blemish in catalogues of synonymous headings. Having so decided, it will prevent future mistakes if a cross-reference is immediately written and sorted into place with the first lot of slips alphabetized when it at once serves as a pointer in the right direction by preventing books upon a single subject being placed under two headings. Thus if the book in hand is
Newth, Samuel. A first book of natural philosophy. pp. viii., 136, illus. sm. 8o. 1867
and the cataloguer has decided in favour of the heading “Physics,” he will at once write a cross-reference
Natural philosophy. See Physics.
which when put in its alphabetical sequence will point out if slips have been inadvertently written under “Natural Philosophy” that the chosen heading is “Physics,” and that the entries must be so altered and arranged. The subject-entry in this instance would be
Physics:
Newth, S. First book of natural philosophy. 1867
It will be here noted that under the subject-heading the author’s surname leads off as it directs to the principal entry where the fullest particulars concerning the book are to be found, and consequently it is most unusual to give the collation, size, and other information in all sub-entries. It is advisable, however, to give the date of publication in every entry excepting in the case of works of fiction under the circumstances referred to in paragraph 24.
77.—The forms of subject entries in dictionary catalogues can be much better shown by means of example with explanations than by statement alone, and for this reason a number of ordinary books, not selected for any difficulty they present, are given. These have been fully worked out in the dictionary system, and are accompanied in each case by the principal entry, so that the complete series of entries can be seen. The styles of types in printing commonly made use of to mark distinctions are also shown.
Abney, W. de W.