JUL 5 )^ ' 



PROCEEDINGS 



^^^^ 



OF THE 



American Philosophical Society 



HELD AT PHILADELPHIA 



FOR PROMOTING USEFUL KNOWLEDGE 



Vol. LVI. 



1917. 



No. 3. 



CONTENTS 



PAGE 



Symposium on Aeronautics. 



I. Dynamical Aspects, By ARTHUR Gordon Webster i6i 



II. Physical Aspects. By George O. Squier i68 



III. Mechanical Aspects. By W. F. Durand 170 



IV. Aerology. By William R. Blair 189 



V. Theory of an Aeroplane Encountering Gusts, II. By Edwin Bidwell Wilson 212 



VI. Engineering Aspects. By Jerome C. Hunsaker 249 



VII. Remarks on the Compass in Aeronautics. By Louis A. Bauer 255 



Spectral Structure of the Phosphorescence of Certain Sulphides. By Edward L. Nichols . 258 



A New Babylonian Account of the Creation of Man. By George A. Barton 275 



The South American Indian in his Relation to Geographic Environment. By WiLLiAM Curtis 



Farabee 281 



PHILADELPHIA 



THE AMERICAN PHILOSOPHICAL SOCIETY 



104 South Fifth Street 



1917 



