In 1755 the Harleian MSS. were removed into it, and the following year the other collections were added, and when all had been properly distributed and arranged the British Museum was opened for public inspection on the 15th of January, 1759. The government of the Institution was vested in trustees, to the end that, as the Act says: “A free access to the collections may be given to all studious and curious persons at such times, and in such manner, and under such regulations for inspecting and consulting the said collections, as by the said trustees, or the major part of them, may be determined in any general meeting assembled.” The trustees are forty-eight in number. Twenty-three are called official, being the holders for the time being of certain high offices; by these the National interests of Church and State, Law, Science, and Art are presumed to be represented and protected. Of these the Archbishop of Canterbury, the Lord Chancellor, and the Speaker of the House of Commons are termed the _Principal Trustees_. Nine others are called the _Family Trustees_, as representing the families of Sloane, Cotton, Harley, etc., etc.; one is termed the _Royal Trustee_, because nominated directly by the Crown. The remaining fifteen are styled the _Elected Trustees_, who are all chosen by the other twenty-three. In accordance with the desire of Sir Hans Sloane, the _elected_ were chosen in the beginning from among the adepts in learning and science, and this practice continued until about 1791, when the vacancies began to be filled almost exclusively by persons of rank and fortune. The chief officer of the British Museum is styled the _Principal Librarian_, which is to a certain extent a misnomer, as he has no more to do with the books than with the other portions of the collection; he derives his appointment from the Crown under sign manual, and is entrusted with the care and custody of the Museum, his duty being to see that all the subordinate officers and servants perform their respective duties properly. The different departments are each managed by a head called _Keeper_, and in most of them there is also an _Assistant-Keeper_, besides assistants and attendants. The patronage of the Museum is vested in the three Principal Trustees, of whom the Archbishop of Canterbury takes precedence. The hours for the opening of the Museum in 1759 were from 9 o’clock in the morning till 3 in the afternoon, from Monday to Friday between the months of September and April inclusive, and also at the same hours on Tuesday in May, June, July, and August, but on Monday and Friday only from 4 o’clock till 8 in the afternoon during these four months.