50 



Mr. W. H. Dines. 

 Concave surface facing the wind. 



[June 4, 



Position I. 



Angle of Value of 



incidence. moment. 



Ill, 116 



22f 116 



45 *124, 130 



Position II. 



Angle of 

 incidence. 



Yalue of 

 moment. 



22f 



118 



45* 117, *113 



Convex surface facing the wind. 







221 

 45 



86 

 65 



43 



45 



76 



46 



Table Y. Chord of Cylinder inclined to the Wind. 



Same plate as in Table II. Chord 9 in. 



Concave surface facing the wind. 



Position I. 



Angle of 

 incidence. 

 ., 

 20 . 



40 



Value of 

 moment. 



. 131 

 .*152 



Position II. 



Angle of 

 incidence. 



Value of 

 moment. 



20 120, 130 



40 . 134 



20 45,46 



Convex surface facing the wind. 



64 



20 



24 



40 



56 



24 



Experiments for the purpose of finding how the curvature influences 

 the resistance at perpendicular incidence have also been made. 



The curvature of the plate was gradually increased by drawing the 

 opposite edges more closely together, and the corresponding pressures 

 were obtained, both with the concave and convex surfaces facing the 

 wind. 



The projection of the plate upon a plane perpendicular to the wind 

 direction becomes less as the curvature increases, but the pressures 

 have been reduced to unit area, so that they may be easily comparable. 

 It should be noted, however, that the pressure upon a rectangle is less 

 than upon an equal square, the difference being considerable if the 

 rectangle be long and narrow. 



The results are given in the following table : 



