Early in his museum career, besides editing a volume of Himyaritic inscriptions, Franks successfully performed the responsible duty of managing the purchases at the Bernal sale in 1855, for which the government had granted 4,000l. a large sum in those days of small prices. The allegation often made in parliament and elsewhere, that at this sale the South Kensington Museum (then at Marlborough House) and the British Museum competed against each other, is untrue, for at the Bernal, as at later sales, the two institutions employed the same agent, and were in daily consultation with regard to their respective purchases. When in 1860 Edward Hawkins (1780-1867) [q.y.] retired from the keepership of the unwieldy department of antiquities, which included all the antiquarian side of the museum, with the addition of the print-room, it was divided into sections ; and finally, in 1866, the arrangement now in existence was inaugurated, under which Franks was appointed the keeper of the department of British and mediæval antiquities and ethnography. Franks was a friend of the ethnologist, Henry Christy [q. v.], and Christy's important museum of ethnological remains was left, on his death in 1865, to trustees, of whom Franks was one. By Franks's efforts the collection was presented to the British Museum, but the collection remained in Christy's house in Victoria Street until 1883, when, by the removal of the natural history collections to South Kensington, room was at last found for it in the buildings at Bloomsbury. Ethnology was a new subject to Franks, but his energy and perseverance were equal to the task, and he arranged the collection in Victoria Street so that the public could be admitted to study it, and made such considerable additions, chiefly from his own resources, that by the time it reached the British Museum it was more than twice its original size.
During the early years of his career at the museum Franks took a special interest in ceramics, and greatly helped Joseph Marryat in his book on 'Pottery and Porcelain' (1851). He made a collection of both English and foreign porcelain and pottery, and some of the finest examples of Italian majolica in the British Museum were presented by him as early as 1855. At a later date, in order to provide the trustees of the British Museum with a material argument in favour of a special grant for purchases at the Fountaine sale [see Fountaine, Sir Andrew], he offered to present objects equal in value to the grant applied for, viz. 3,000l., and the application was successful. The porcelain of China and Japan had always attracted him, and he aimed at making as comprehensive a collection as possible. He exhibited his collection of eastern ceramics at the Bethnal Green Museum in 1876, and printed a catalogue, of which a second edition appeared in 1878, when he presented the collection to the British Museum, though it was not removed thither until 1884. The catalogue was prepared with great care and still remains a standard work on the subject. His interest in oriental art was not, however, confined to pottery ; he made a large collection of oriental art of diverse kinds, some of which he gave to the museum at intervals, while retaining certain classes of objects in order that the series might be made more perfect, and that duplicate or inferior pieces might be eliminated. He thus kept in his possession until his death the collection of Japanese sword-guards and ivory carvings (netsuké), partly with the object just mentioned, but more especially with a view to carrying out the plan he had long cherished of preparing and printing catalogues of the various collections he had formed before presenting them to the nation the end he always had in view. A great quantity of material for these catalogues had been gathered, but he was not destined to carry out the scheme in full, and the catalogues of the oriental porcelain and of a collection of continental porcelain, now at Bethnal Green, are all that he was able to complete. Another of his most important collections was that of ancient finger rings, of which he possessed a series quite unequalled, while drinking-vessels of all kinds and materials formed another definite class ; this collection was for many years during his lifetime on loan at the British Museum. Less well known was the extraordinary collection of objects in gold from Bactria of the time of Alexander the Great or earlier, which Franks obtained through Indian dealers, and augmented by acquiring the collection of Sir Alexander Cunningham [q. v. Suppl.] In addition to these he had a good collection of mediæval and later jewellery, as well as several interesting finds of the later classical period. The whole of these various collections passed under his will to the British Museum.
The one acquisition of recent times of which he was justly proud was the famous enamelled gold cup of the kings of France and England, which had figured in the English royal treasury from Henry VI to James I. This he secured in 1892 for the British Museum from Messrs. Wertheimer, who ceded it at the price of 8,000l. they had paid its previous owner, Baron Pichou. In the first instance he actually bought the cup himself,