This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Very often it is found, after arranging the books in a case, that the rows are not complete and the books at the end are continually sliding down on the shelf. The sketch shows a very useful type of wire bracket to support the last book.
Ill: The Shape of the Wire Makes It Easily Applicable to Any Open Bookshelf
A brass wire, 26 in. long and about 1/8in. in diameter, is bent, with the use of a vise or pliers, to the shape and dimensions shown at A. When the wire is placed on the bookshelf, as shown at B, it prevents the end book from falling. Its location can be changed as books are added to the shelf. - Contributed by John Y. Dun-lop, Craighead, Scotland.