[55] The present writer, in his paper quoted on page 229, pointed out the equilibrative and steadying quality of torsionally elastic wings, and some years previously had proved this by gliding models having sustainers with flexible rear margins.
[56] The whole water vapor in the atmosphere of our latitude in summer is equivalent to about one inch of rainfall.
[57] Computed by W. J. Humphreys for Moore’s Descriptive Meteorology.
[58] Ferrel, Popular Treatise on Winds.
[59] Solar radiation received by the earth.
[60] W. J. Humphreys, Astro. Phys. Journ., January, 1909.
[61] An isobar is a line of intersection of an isobaric surface with a water level surface at any altitude.
[62] A Popular Treatise on the Winds.
[63] The Conquest of the Air.
[64] By this current John Wise, in 1870, and Walter Wellman, in 1910, proposed to voyage across the Atlantic; Wise in a free balloon, Wellman in a motor balloon with drag rope. See pp. 74, 75.