Ellis and Baber's catalogue had scarcely been completed ere the need of a new one began to be felt, partly on account of the magnificent donation of the 60,000 volumes and 20,000 pamphlets of the King's Library. Notions of classification were then in the ascendant, and in 1826 the Rev. T. Hartwell Horne, a bibliographer famed for strict method and plodding industry, was engaged as a temporary assistant to carry them out; together with Mr. (afterwards Sir Frederic) Madden, Mr. Tidd Pratt, and other persons of literary ability. Seldom has an undertaking so extensive left so little trace behind it. Mr. Horne's assistants ascended to higher spheres, or evaporated entirely, and when called upon in 1834 to report the progress of the previous year, he could only state that he had personally arranged the classes of "chemical and medical philosophy"; the latter, indeed, under twenty divisions, with such subdivisions as "Treatises on Plethora," "Treatises on the Vis Medicatrix Naturæ," "Use of Flagellation, Friction and Philtres." The list may be commended to the study of those who think classification a simple matter, or a classed catalogue serviceable otherwise than as an index to an alphabetical one. Seven thousand pounds had been expended upon the simple sorting of titles, a task merely preliminary to that of printing them, which might be considered as at least nearly half done, if only the influx of new titles could be stopped, which was impossible. The Trustees wisely determined to throw no more good money after bad; and the episode of classification came to an end in July 1834. Mr. Baber, Keeper of Printed Books, had already proposed a plan for a new printed catalogue, to be executed under the superintendence of a single competent person, a description denoting Panizzi, then "an extra assistant librarian." This scheme was set aside in favour of a far inferior plan, by which the execution of the catalogue was entrusted to four persons of very unequal degrees of capacity, virtually independent of each other. The consequence was that the little they did required to be done again. Panizzi became head of the Printed Book Department in 1837, and the long discussions which ensued between him and the Trustees resulted eventually in the ninety-one famous rules which have since formed the foundation of scientific cataloguing drawn up by him with the assistance of Messrs. Winter Jones, Watts, Parry, and Edwards. Their number has afforded a theme for much good-natured and ill-natured satire; on examination, however, it will be found that a third of them relate merely to arrangement, and that the remainder are far from providing for all conceivable cases. It may be granted that their complexity was incompatible with the Trustees' desire to produce a printed catalogue at an early date, a desire in which their officer was far from participating. The Trustees defeated their own object, partly by allowing the catalogue to be commenced on so extensive a scale;