ALPHAETICO - CLASSED CATALOGUE:
The alphabetico-classed catalogue may be considered as a combination or mixture of the best points associated with dictionary and classified catalogue. In other words, it represents an attempt to combine some of the advantages of a classified catalogue with the directness and ease of consultation of the -alphabetical catalogue. An alphabetico-classed catalogue provides alphabetically arranged broad subject headings with alphabetically arranged sub-divisions". (Hunter and Bakewell). "A catalogue of this kind consists of an alphabetical sequence of mutually exclusive broad subject headings, under each of which appears of further alphabetical sequence of sub-headings. The process of alphabetical divisions can be carried down to the degree of minuteness required by the material being catalogue". (E. J. Coates). The rearrangement of Dewey Decimal Classification division of 600 Technology in an alphabetical order would yield the following.
Agriculture and related technologies (630) Building (690) Chemical and related technologies (660) Engineering and allied operations (620) Home Economics and family living (640) Management and auxiliary services (650) Manufactures (670) Manufacture of product for specific uses (680) Medicine (610) Diseases (616) of blood - forming, lymphatic, glandular system (614.4) cardiovascular system (616.1) digestive system (616.3) of hillary tract (616.36) of mouth and throat (616.31)
This type of catalogue must have an alphabetical index of specific subject for its successful operation.
As will be seen from the above examples, the alphabetico-classed catalogue gets related subjects together in a way, but their alphabetical arrangement takes away the filiation of subjects. There are few examples of such catalogues today, because compromises are never entirely successful.
Parts of the original Museum subject index use the alphabetico-classed principle.