Strehlke on the Acoustic Figures of Plates. 297 



In a square plate of copper (No. 3.) of 34'".3 in length, and 

 l w .33, the equation for B was found to be 



2/ = 1027 . x . (x + 3"'-846), 



and the distance between the two summits 3"'-88 ; the results 

 of observation and calculation agree in the following manner : 



In order to ascertain whether the distance of the summits 

 was in any way related to the length of the side of the plate, 

 this distance was measured on a great number of plates, and 

 then compared with the length of the side. In the following 

 table 2a is the distance in decimal fractions, the entire length 

 of the side being I'OOO, and <p the angle between the asymptote 

 of the hyperbola, and the principal axis. 



X 2 



