44 



EXPERIMENTS IN AERODYNAMICS. 



Table XI.— August 24, 1889. 

 Barometer, 734.3 mm.; mean temperature, 25°.0 c. ; wind, light. 



The actual velocities obtaining in the individual observations varied some- 

 what : for the lowest velocity ranging between 5 and 8; for the second velocity 

 ranging between L2.5 and L3.5, and for the highest velocity ranging in gen- 

 eral between 22.5 and 24.0, except for the planes 6 inches apart, for which the 

 velocities were about l'.» meters per second. The numerical results for the 

 lowesl and the highest speed will be found plotted in Figs. <> and 7, respectively, 

 in these diagrams the abscissae are angles of inclination of the planes to the 

 horizon, and the ordinates are times of falling. For f ho highest velocity, the 

 t imes wf falling uf the single pair of planes and of the double pair, both, 4 inches 

 and 6 inches apart, are alike, while for the planes 2 inches apart, the time of falling 



is shorter. For the lowest velocity, viz., (>.") meters per sei d, the planes 4 inches 



apart as well as tlmse 2 inches apart fall a little faster than the single plane, 

 and are therefore not quite so well sustained by the air. 



This result confirms tin' statement above made, that for double sets of plane.-, 

 une above the other, the maximum supporting effect relatively to the single 



