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; partly by requiring, or rather letting themselves be thought to have required, that it should be actually printed, instead of merely ready for press, by December 1844. This decision necessitated printing in alphabetical succession, hence diverting much of the force which should have been applied to compiling the catalogue, to the correction of the press. It further condemned the work to inevitable imperfection, since it was impossible to foresee what titles would be required to be written under A, and such titles, excluded from the printed volume embracing that letter, kept continually turning up during the entire progress of the work. As the imperfections of this volume (published in 1841) became more notorious, the demand for a printed catalogue gradually died away, and Panizzi was left in possession of his ideal—a manuscript catalogue, executed with a thoroughness and on a scale which seemed to render printing for ever impossible. This, as we shall see, was destined to break down in its turn; and the great librarian's objections to print have met with a practical refutation. At the same time it must be candidly acknowledged that, although Panizzi was wrong in abstract principle, he was right as regarded the requirements of his own day. The collection of books was at the time too limited to justify a printed catalogue, and not too extensive to render a manuscript catalogue inconveniently unwieldy. Panizzi's opposition to print was justifiable under the circumstances then existing; his error was in failing to foresee and provide for the far different state of things which he himself was calling into existence.