Much attention has been given to devices for adjustment of shelves. Some of these are quite ingenious and a few are satisfactory. No device should be introduced that will seriously break the smooth surface at the side. Notches, cross bars, iron horns or hooks or ornamental brackets expose the last book to damage. If pins are used they should be so held to their places that they cannot fall out. Heads of pins or bars should be sunk in the wood and the place for books left, as near as possible, absolutely smooth on all sides. It is at least a question whether the importance of making shelves adjustable and absolutely adjustable has not been greatly overrated. As a fact the shelves of the circulating library are very seldom adjusted. They may have all the usual appliances gained at large expense but there is no occasion to adjust them outside the reference room. They remain as they were put up. It is probably well to have the second and third shelf movable so that one can be dropped to the bottom and two spaces left where there were three at first. But all other shelves might as well be fixed at intervals of 10 inches without the least real inconvenience and the cases be stronger for it and far cheaper. A perfectly adjustable shelf is interesting as a study in mechanics, but is practically disappointing. Its very perfection is a snare because it is so impossible to set it true without a spirit level and a machinist. All shelves in a reference room should be adjustable. Bound magazines might have special cases. _Wood or iron shelves._ Iron shelf construction has the advantage of lightness and strength, filling the least space and admitting light and air. Where three or more stories of cases are stacked one upon another iron is a necessity. It also offers the best facilities for adjustment of shelves and is most durable. On the other hand it is more difficult to get, can be had only of the manufacturers in fixed patterns, and costs at least twice as much as any wood, even oak, unless carved for ornament, and four or five times as much as some very good wooden shelves. This great cost raises the question whether the advantages named are really important. Few village libraries need more than two stories of shelves in a stack. If iron is more durable we can buy two sets of wooden shelves for the cost of one of iron--and when we buy the second set will know better what we want. The importance of shelf adjustment has been exaggerated. A more important consideration, to my mind, is that iron is not so well adapted to the changing conditions of a growing library. It is made at a factory and to be ordered complete. It is bolted to the floor and wall at fixed intervals. But we have seen that a gradual accumulation of bookcases is better than to put all shelving in position at first.