the nails taken out of the corresponding holes. From this primitive contrivance, which was behind the counter and used only by the assistants, all the various forms of indicators, used either by the public or by the attendants only, have sprung.
Indicators may be divided into two kinds, namely, those which only show if the books are in or out, and those which combine with this a system of book-keeping and issue recording. One of the earliest of the latter kind is that invented by Mr. John Elliot, of the Wolverhampton Library (Fig. 25). It consists of a wooden frame, with a series of uprights at a distance of about 2 inches from each other. These are connected by shelves of tin, placed about ⅜ of an inch apart. Numbers corresponding to the books are pasted to the uprights, one being placed opposite to each tin shelf. The method of work is simple. When a person joins the library he is given a reader's ticket, formed of thick millboard, folded like a book, with two or more pages of plain paper in it. This ticket is retained by the borrower when he has not got a book, and is kept by the librarian when a book is issued. If book No. 608 is wanted, for instance, the borrower looks for the number on the indicator, and if the shelf on the right of the number is empty, he knows that it is in, and asks for it at the issue desk. The attendant fetches the book from the shelf, stamps the date and the book number on the borrower's ticket, and then places it on the tin shelf in the indicator corresponding to the number. It remains there until
