CHAPTER V.
REFERENCES AND SUBJECT INDEX.
I suppose it may be conceded that in the abstract the most useful kind of catalogue is that which contains the titles and subject references in one alphabet; but in the particular case of a large library this system is not so convenient, because the subject references unnecessarily swell the size of the catalogue, and by their frequency confuse the title entries. For instance, it is something appalling to conjecture what would be the size of the British Museum Catalogue if subject references were included in the general alphabet. In the case of a large library it will be more convenient to have an index of subjects forming a separate alphabet by itself, and this cannot be made until the catalogue of authors is completed. Taking a somewhat arbitrary limit, it may be said that in libraries containing more than ten thousand volumes it will be found more useful to have a distinct index of subjects, while in catalogues of libraries below that number it will generally be advisable to include the subject references with the titles in one general alphabet.
If all the subject references are reserved for an index, there will still remain a large number of references in the general alphabet which are required for the proper use of the catalogue; and here it may be well to say something as to the nomenclature of references. Mr. Cutter, in the valuable series of definitions prefixed to his Rules for a Dictionary Catalogue, has the following:—
"Reference, partial registry of a book (omitting the imprint) under author, title, subject, or kind, referring to a more full entry under some other heading; occasionally used to denote merely entries without imprints, in which the reference is implied. The distinction of entry and reference is almost without meaning for Short, as a title-a-liner saves nothing by referring unless there are several references.
"Analytical reference, or simply an analytical registry of some part of a book or of some work contained in a collection, referring to the heading under which the book or collection is entered.
"Cross reference, reference from one subject to another.
"Heading reference, from one form of a heading to another.
"First-word reference, catch-word reference, subject-word reference, same as first-word entry, omitting the imprint and referring."
These definitions are important, and it would be well if the distinction here made as to what a cross-reference really is were borne in mind. It has become the practice among bibliographers to describe all references as cross-references. This is the case in the British Museum rules:—
"LV. Cross-references to be divided into three classes, from name to name, from name to work, and from work to work. Those of the first class to contain merely the name, title, or office of the person referred to as entered; those of the second, so much of the title referred to besides as, together with the size and date, may give the means of at once identifying, under its heading, the book referred to; those of the third class to contain moreover so much of the title referred from, as may be necessary to ascertain the object of the reference."
The public often cause a still further confusion in words, for they cry out for the shelf-marks to be placed to references. If this be done, they no longer remain references, but become double entries.