Even the classed catalogues often have specific entry. Whenever a book treats of the whole subject of a class, it is specifically entered under that class. A theological encyclopædia is specifically entered under Theology, and theology is an unsubordinated class in many systems. The alphabetico-classed catalogues have specific entry in many more cases, because they have many more classes. Professor Abbot has such headings as Ink, Jute, Lace, Leather, Life-savers, Locks, Mortars, Perfumery, Safes, Salt, Smoke, Snow, Varnish, Vitriol. Mr. Noyes has scores of similar headings; but neither of them permits individual entry, which the dictionary-catalogue requires. The alphabetico-classed catalogue enters a life of Napoleon and a history of England under Biography and History; the dictionary enters them under Napoleon and England. This is the invariable and chief distinction between the two.