1950. First Edition. 154 pages. Dust jacket over red cloth. Black and white illustrations throughout. Methuen's Monographs on physical subjects series. Clean pages with mild tanning throughout. Tightly bound with faint thumb-marking throughout. Small droplet, previous owner's inscription and stamping to front endpaper. Boards have light shelf-wear with corner bumping. Mild mottling to boards. Unclipped jacket has moderate edgewear with chips, tears, and creasing. Notable droplet marks to front panel. Heavy tanning to spine. Light rubbing and marking all over.