Lot 250
4 vols. PIERCY N. A. V. Aerodynamics, London: English Universities Press, 8vo, 536pp. Second Edition 1947, signed B.N, Wallis to endpaper. ROARK Raymond J., Formulas For Stress and Strain, London: McGraw Hill 1954, 8vo, 432pp., signed B.N. Wallis to endpaper. BRAGG S. L. Rocket Engines, London: George Newnes Ltd. 1962, 8vo, 158pp. Signed B.N. Wallis 1977 to end paper and PALMGREN Arvid, Ball and Roller Bearing Engineering, USA: Burbank 1946, 4to, 270pp., signed B.N. Wallis Feb '48 to endpaper  £60-80