Descendenz und Hybriden. 9 



Formulae are given for finding the first six moments for a 

 System of ordinates and the method is illustrated by fitting a 

 variety of curves to various biological data. 



The moments for a System of trapezia are also found and 

 a table of corrective terms is provided. 



The fitting of Parabolic curves is investigated and expressions 

 found for the values of the constants up to Parabolas of the 

 sixth Order, geometrical construction is also given for fitting 

 straight lines. 



Some examples are worked out, and it is pointed out that 

 the method of moments for Parabolic curves has the same 

 basis as that of least Squares but is much easier of application. 



Karl Pearson. 



Weldon, W. f. R., Change in Organic Correlation of 

 Ficaria Ranunciiloides during the Flowering Season. 

 (Biometrika. Vol. I. Part I. 1902. p. 125—128.) 



The author shews that the importance of the results ob- 

 tained by Professor Mac Leodin dealing with the changes, 

 during a single flowering season, of the correlation between 

 the number of stamens and the number of pistils of this plant, 

 is obscured by the adoption of Dr. Verschaff elt's method 

 which falls to distinguish between regression and correlation, 

 Mac Leod's tables are reprinted and the results are expressed 

 in Galton 's notation, they show that the correlation is 

 distinctly less in early than in late flowers; whereas Mac Leod 

 obtains a correlation greater than unity, which he interprets 

 as a sign of imperfect correlation and consequently describes 

 the change in correlation as the reverse of what actually 

 happens. 



Attention is drawn to the fact that Mac Leod's investi- 

 gations shew the danger of assertfng that differences in mean, 

 variability, and correlation during the flowering season are 

 necessarily significant of local races. Karl Pearson. 



Weldon, W. F. R., On the Ambiguity of Mendel 's 

 Categories. (Biometrika. Vol. II. Part I. 1902. p. 44 

 —5b.) 



The author draws attention to the ambiguity caused by 

 following Mendel's System of dividing a set of variables into 

 two categories, he takes as examples the terms „green", and 

 „yellow" and illustrates the fact that they are not quantitatively 

 definite by taking a scale of colour A D of which the ränge AB 

 includes various shades of green, and the ränge C D of yellow 

 and shews that if two races are crossed and the cotyledons 

 of the one fall into the ränge A B and of the other into the 

 ränge C D there is no justification for saying that the exact 

 shade of the hybrid is that of a particular member used in the 

 cross — he then considers the terms „glabrous'' and „hairy" 



