=AERIAL FLIGHT. Vol. 1. Aerodynamics.= By F. W. LANCHESTER. 8vo., cloth, 438 pp., 162 illustrations =$6.00 net= =CONTENTS=: Fluid Resistance and Its Associated Phenomena. Viscosity and Skin Friction. The Hydrodynamics of Analytical Theory. Wing Form and Motion in the Periphery. The Aeroplane. The Normal Plane. The Inclined Aeroplane. The Economics of Flight. The Aerofoil. On Propulsion, the Screw Propeller, and the Power Expended in Flight. Experimental Aerodynamics. Glossary. Appendices. =Vol. II. Aerodonetics.= By F. W. LANCHESTER. 8vo., cloth, 433 pp., 208 illustrations =$6.00 net= =CONTENTS=: Free Flight. General Principles and Phenomena. The Phugoid Theory--The Equations of the Flight Path. The Phugoid 1852-1872. Dirigible Balloons from 1883-1897; 1898-1906. Flying Machine Theory--The Flight Path Plotted. Elementary Deductions from the Phugoid Theory. Stability of the Flight Path as Affected by Resistance and Moment of Inertia. Experimental Evidence and Verification of the Phugoid Theory. Lateral and Directional Stability. Review of Chapters I to VII and General Conclusions. Soaring. Experimental. Aerodonetics. =AERIAL NAVIGATION. A practical handbook on the construction of dirigible balloons, aerostats, aeroplanes and aeromotors=, by FREDERICK WALKER. 12mo., cloth, 151 pp., 100 illustrations =$3.00 net.= =CONTENTS=: Laws of Flight. Aerostatics. Aerostats. Aerodynamics. Screw Propulsion. Paddles and Aeroplanes. Motive Power. Structure of Airships and Materials. Airships. Appendix. =AEROPLANE PATENTS.= By ROBERT M. NEILSON. 8vo., cloth, 101 pp., 77 illustrations =$2.00 net= =CONTENTS=: Advice to Inventors. Review of British Patents. British Patents and Applications for Patents from 1860 to 1910, arranged in Order of Application. British Patentees, arranged alphabetically. United States Patents from 1896 to 1909, arranged in order of issue. United States Patentees, arranged alphabetically. =THE PRINCIPLES OF AEROPLANE CONSTRUCTION.= By RANKIN KENNEDY, C. E. 8vo., cloth, 145 pp., 51 diagrams =$1.50 net= =CONTENTS=: Elementary Mechanics and Physics. Principles of Inclined Planes. Air and Its Properties. Principles of the Aeroplane. The Curves of the Aeroplane. Centers of Gravity: Balancing; Steering. The Propeller. The Hélicoptère. The Wing Propeller. The Engine. The Future of the Aeroplane. =HOW TO DESIGN AN AEROPLANE.= By HERBERT CHATLEY. 16mo., boards, 109 pp., illustrated (Van Nostrand's Science Series) =50 cents= =CONTENTS=: The Aeroplane. Air Pressure. Weight. Propellers and Motors. Balancing. Construction. Difficulties. Future Developments. Cost. Other Flying-Machines (Gyroplane and Orinthoptere).