40 



NATURAL INHERITANCE. 



[CHAP. 



of Eank (on a scale reckoned from to 100) of any 

 person in the group to which he belongs. The measured 

 strength of the person is to be looked for in the side 

 scale of the Scheme ; a horizontal line is thence drawn 

 until it meets the curve ; from the point of meeting 

 a perpendicular is dropped upon the scale of Grades 

 at the base ; then the Grade on which it falls is 



FIG .4. 



Us. 



vx> 



i- so 



50' 



icxf 



FIG. 5 



o 



0' 



TOO' 



FIG .6. 



M 



ion 9 



the one required. For example : let us suppose the 

 Strength of Pull of a man to have been 74 Ibs., 

 and that we wish to determine his Rank in Strength 

 among the large group of men who were measured 

 at the Health Exhibition in 1884. We find by Fig. 

 4 that his centesimal Grade is 50; in other words, 

 that 50 per cent, of the group will be weaker than 

 he is, and 50 per cent, will be stronger. His 



