1921. No edition remarks. 158 pages. No dust jacket. Pictorial cloth covered boards. Black and white diagrams throughout. Ex libris plate at front. Pages with some foxing and tanning, particularly to endpapers and textblock edges. Binding remains firm. Previous owner's name to front pastedown. Boards have moderate shelf wear with mild bumping and fraying to corners and crushing and fraying to spine ends. All surfaces tanned and sunned, particularly spine. Gilt lettering to spine is dulled but remains brighter on front.