134 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



508 



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



Eddystone Light. Mean, 17,478 J^ .029 rays ; stand, dev., 1.000 J- .020 rays ; 

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



At2 - 0.999495 M3 = 0.201477 fn = 3.474913 



$i = 0.040654 )3o = 3.47842 Crit. funct. (k^) = 0.037046 



.-. Type IV. Skewness = 0.08015 ; mode at 16.6955. 



Comparison of Empirical and Theoretical Polygons. 



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

 var., 5.931 ^ .114%. 



yu.2 = 1.152672 M3 = 0.219822 ^4 = 4.09141 



b\ - 0.031552 /82 = 3.079312 Crit. funct. (kj) = 0.06398 



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



Comparison of Empirical and Normal Polygons. 



