The essential feature of the present work has been the insistance on the importance of a somewhat unfamiliar idea that rapid aerial locomotion can be effected by taking advantage of the inertia of the air and its elasticity. Though the fact that the air has inertia is a familiar one, and though the flight of certain missiles has indicated that this inertia may be utilized to support bodies in rapid motion, the importance of the deductions to be made has not been recognized. This work makes the importance of some of these deductions evident by experiment, and perhaps for the first time exhibits them in their true import.

This memoir is essentially a presentation of experiments alone, without hypotheses, and with only such indispensable formul as are needed to link the observations together. These experiments furnish results which may be succinctly summarized as follows:

The primary experiment with the Suspended Plane is not intended per se to establish a new fact, but to enforce attention to the neglected consequences of the fundamental principle that the pressure of a fluid is always normal to a surface moving in it, some of these consequeuces being (1) that the stress necessary to sustain a body in the air is less when this is in horizontal motion than when at rest; (2) that this stress instead of increasing, diminishes with the increase of the horizontal velocity (a fact at variance with the conclusions of some physicists of repute and with ideas still popularly...