52 



Life and Letters of Francis GaUon 



a 

 G 



X 



six characters: Head Length, Head Breadth, Stature, Length of Left 

 Middle Finger, Left Cubit and Height of Right Knee. But he only provides 

 as illustration one table such as we now term a correlation table, and one 

 diagram illusti'ating how he found what we now term the correlation co- 

 efficient. The table and diagram dealing with the co-relation of stature and 

 cubit are given below. Readings were made to one-tenth of an inch. 



Correlation Table for Stature and Cubit. 



Length of Left Cubit in inches, 348 adult Males. 



* Printed as 48, 48, and 34 respectively in the Roy. Soc. Proceedings. 



Diagram illustrating the Graphical Process of finding the Slope of the 

 Regression Line, i.e. the Correlation Coefficient of to-day's terminology. 



Fig. 11. 



Galton says he constructed tables and diagrams like the above. " It will 

 be understood that the Q value is a universal unit applicable to the most 

 varied measurements, such as breathing capacity, strength, memory, keenness 

 of eyesight, and enables them to be compared together on equal terms not- 

 withstanding their intrinsic diversity. It does not only refer to measures of 



