W. L. Tower 315 
15 20 25 30 35 40 
15 20 25 30 35 40 
Fig. 1. «=284; ?)i2 = 27-S7; modes = '22, S3. 
Fig. 2. n=W8; ?»3 = 21-36; modes = lS, 21. 
Fig. 3. n = 452 ; 24-62 ; modes = 13, 21, 33. 
32—2 
