(a.) ENTRIES CONSIDERED SEPARATELY.
92. Some questions in regard to the place of entry are common to the author- and the subject-catalogue; because individuals (persons, places, ships, etc.) may be at once authors and subjects. For these questions consult Part I, and also § [100] of the present part.
In a dictionary catalogue some books can not profitably have subject-entry, because they not only have no one subject but do not even belong to any class of subjects.
A collection is to be entered under the word which expresses its subject or its general tendency. The memoirs, transactions, proceedings, etc., of a society should be entered under name of the object for which the society is founded. When there are many societies under one head, it is economical to refer merely; as, from Agriculture or Agricultural societies to the various names.
The importance of deciding aright where any given subject shall be entered is in inverse proportion to the difficulty of decision. If there is no obvious principle to guide the cataloguer, it is plain there will be no reason why the public should expect to find the entry under one heading rather than another, and therefore in regard to the public it matters not which is chosen. But it is better that such decisions should be made to conform when possible to some general system, as there is then more likelihood that they will be decided alike by different cataloguers, and that a usage will grow up which the public will finally learn and profit by, as a usage has grown up in regard to the author-entry of French names containing De, Du, La, etc.
(i.) CHOICE BETWEEN DIFFERENT SUBJECTS.
(a.) Between general and specific.
93. Enter a work under its subject-heading, not under the heading of a class which includes that subject.
Ex. Put Lady Cust’s book on “The cat” under Cat, not under Zoölogy or Mammals, or Domestic animals; and put Garnier’s “Le fer” under Iron, not under Metals or Metallurgy.
This rule of “specific entry” is the main distinction between the dictionary-catalogue and the alphabetico-classed.