1946. Sixth Edition. 503 pages. Green dust jacket over blue cloth. Contains black and white folded diagrams and tables. Pages are moderately tanned with noticeable foxing throughout. Slight crinkling to paper at gutters, however binding remains firm. Folded diagrams and tables are mildly tanned with small tears to edges. Occasional thumb-marking. Boards have slight edge wear with corner bumping. Mild tanning to spine and edges with some crushing to spine ends. Gilt lettering is bright and clear. Book has a slight forward lean. Unclipped jacket. Panels have moderate edge wear with chips, tears and creasing. Small area of loss to edges. Black marks overall.