266pp, many black and white diagrams and photographs. Light blue cloth-covered boards with red titles on the spine and front. 12mo. Fading to spine and top and bottom edges of boards, a few very small marks and stains on boards, spine ends and corners lightly rubbed and rounded. Text block edges tanned and starting to fox. Bookseller's label on front pastedown, light foxing to prelims; tanning to page margins. Otherwise internally neat, clean and tight. Including special chapters on illumination, motors and generators.
