THE COUNTERPOISED ECCENTRIC PLANE. 



91 



Table XVII. 



Summary of Experiments giving position of center of pressure on a plane one foot square {30.5 x S0.5 



centimeters) for different angles of inclination. 



The first two columns give the distance from the center of pressure to the center 

 of the plane in centimeters and inclies, and the third column gives it as a per- 

 centage of the length of the plane. The fourth column gives the angle of trace 

 with the initial vertical line drawn through the position of the pencil at rest. It 

 will be noticed that this angle is 5°.5 for the case when the axis of rotation passes 

 through the center of the plane — a setting for which the plane must be vertical. 

 This observed angle of 5° .5 is to be explained, not by a tipping of the plane, 

 but by a tipping of the line of reference due to a yielding of the supports, etc., to 

 the wind of rotation. This angular deflection, therefore, becomes a correction to 

 be applied to all the observations, and the fifth column, headed " angle of plane 

 with vertical," contains the corrected values for the inclination of the plane. 



The resulting relations here established between the angle of inclination of 

 the plane and the position of the center of pressure are of importance, but their 

 application is not made in the present memoir.'^' 



* References to the results of Joessel and of Kummer will be found in Appendix C. 



