Much, however, and far the largest amount of the material in a well-appointed reading room will not be literature at all, but simply information. In the chief London and many provincial libraries a large number of scientific and technical periodicals are taken, including publications of research societies and a good many foreign periodicals. More are required, and, as our public libraries are able to spend more money, one at least in each large area of population ought to be as well provided in this respect as are the science libraries at South Kensington, the university libraries, or, say, the Manchester Literary and Philosophical Institution, to take a good provincial example. These publications are as necessary as it is to keep editions of scientific and technical books thoroughly up to date. Their contents should be fully accessible, and to ensure this every library must subscribe to the Subject-Index to Periodicals. A practice increasing in frequency is that of indexing the current periodicals as they arrive, and mounting the entries in a mechanical guard-book or vertical file. Such libraries as possess a stock of long sets will naturally be provided with Poole’s and the other older indexes to periodicals; even libraries not possessing such long sets ought to have the indexes, for the same reason as they have other bibliographical guides, namely, to show inquirers in what books or periodicals information exists, an intelligent staff being relied upon to point out in what nearest libraries the books or periodicals are to be found. SPECIAL READING ROOMS.