Rules are of two kinds, those which concern the librarian and assistants, and those which concern the public resorting to the library. Of the first class are the regulations as to hours, division of labor, leaves or vacations of employees, &c. The larger the library, and consequently the force employed, the more important is a careful adjustment of relative duties, and of the times and seasons to be devoted to them. The assignment of work to the various assistants will naturally depend upon their respective qualifications. Those who know Latin, and two or more of the modern languages, would probably be employed upon the catalogue. Those who are familiar with the range of books published, in literature and science, will be best qualified for the service of the reading-room, which involves the supply of books and information. In direct proportion to the breadth of information possessed by any one, will be his usefulness in promptly supplying the wants of readers. Nothing is so satisfactory to students in libraries, or to the casual seekers of information of any kind, as to find their wants immediately supplied. The reader whom an intelligent librarian or assistant answers at once is grateful to the whole establishment; while the reader who is required to wait ten to twenty minutes for what he wants, becomes impatient and sometimes querulous, or leaves the library unsatisfied. One rule of service at the library desk or counter should be that every assistant there employed should deem it his duty to aid immediately any one who is waiting, no matter what other concerns may engage his attention. In other words, the one primary rule of a public library should be that the service of the public is always paramount. All other considerations should be subordinate to that. It is desirable that assistants in every library should learn all departments of library work, cataloguing, supplying books and information, preparing books for the shelves, etc. This will enable each assistant to take the place of another in case of absence, a most important point. It will also help to qualify the more expert for promotion. A second rule for internal administration in any library should be that all books are to be distributed, or replaced upon their shelves, daily. If this is not systematically done, the library will tend to fall into chaos. And even a small number of volumes not in their places will embarrass the attendants seeking them, and often deprive readers of their use--a thing to be always sedulously avoided.