In some libraries, and those usually of the larger size, an art room is provided, where students of works on painting, sculpture, and the decorative arts can go, and have about them whatever treasures the library may contain in that attractive field. The advantages of this provision are, first, to save the necessity of handling and carrying so many heavy volumes of galleries of art and illustrated books to the general reading-room, and back again, and secondly, to enable those in charge of the art department to exercise more strict supervision in enforcing careful and cleanly treatment of the finest books in the library, than can be maintained in the miscellaneous crowd of readers in the main reading-room. The objections to it concern the general want of room to set apart for this purpose, and the desirability of concentrating the use of books in one main hall or reading-room. Circumstances and experience should determine the question for each library. Some public libraries, and especially those constructed in recent years, are provided with a lecture-hall, or a large room for public meetings, concerts, or occasionally, even an opera-house, in the same building with the library. There are some excellent arguments in favor of this; and especially where a public benefactor donates to a city a building which combines both uses. The building given by Mr. Andrew Carnegie to the Public Library of Washington will be provided with a small hall suited to meetings, &c. But in all cases, such a public hall should be so isolated from the library reading-room as not to annoy readers, to whom quiet is essential. This end can be effected by having the intervening walls and floors so constructed as completely to deaden sound. A wholly distinct entrance should also be provided, not communicating with the doors and passages leading to the library. Comparisons are sometimes made as to the relative cost of library buildings to the number of volumes they are designed to accommodate; but such estimates are misleading. The cost of an edifice in which architectural beauty and interior decoration concur to make it a permanent ornament to a city or town, need not be charged up at so much per volume. Buildings for libraries have cost all the way from twenty-five cents up to $4. for each volume stored. The Library of Congress, which cost six million dollars, and will ultimately accommodate 4,500,000 volumes, cost about $1.36 per volume. But it contains besides books, some half a million musical compositions, works of graphic art, maps and charts, etc.