134 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



From these seriations the constants have been calculated as follows : — 



Eddystone Light. Mean, 17.478 -|- .029 rays ; stand, dev., 1.000 -j- .020 rays ; 

 coef. of var., 5.72 -J- .12%. 



M 2 = 0.999495 Ms = 0.201477 M4 = 3.474913 



&\ = 040654 B, - 3.47842 Crit. funct. (k 2 ) = 0.037046 



.'. Type IV. Skevvness = 0.08015 ; mode at 16.6955. 



Comparison of Empirical and Theoretical Polygons. 

 y = 165.89 (cos e) 10.519« . C 0.00001G6 fl". 



Irish Sea. Mean, 18.101 -J- .029 rays; stand, dev., 1.074 -J- .021 rays; coef. of 

 var., 5.931 -j- .114%. 



M 2 = 1.152672 M3 = 0.219822 M 4 = 4.09141 



Sj = 0.031552 S, = 3.079312 Crit. funct. { Kl ) = 0.06398 



Type IV, or normal type. (Skevvness, 0.08698.) 



Comparison of Empirical and Normal Polygons. 



100.1 



100.0 



