10 HEREDITY [CH. 



which are not connected by intermediates. Further, 

 in cases of continuous variation it will appear that 

 one size is more common than any other, and, in the 

 simplest cases, that the individuals are progressively 

 rarer as the size of the structure considered diverges 

 more and more from the most frequent value. The 

 most frequent condition is named the ' mode,' and its 

 size the 'modal value' for the character. For ex- 

 ample, if the heights of a large number of men were 

 measured, it might be found that they ranged by 

 every gradation from 60 to 76 inches. If the measure- 

 ments were taken to the nearest inch, it might then 

 be found that a greater number had a stature of 

 68 inches than any other height, that the next most 

 frequent heights were 67 and 69 inches, and that the 

 more the stature differed from 68 inches in either 

 direction, the fewer would be the men having that 

 measurement. This could be represented graphically 

 by arranging vertical lines representing the heights 

 of every man in order of their height ; a line joining 

 their tops would then rise rapidly at the lower end, 

 would be nearly flat as it passed over the men having 

 heights near the 'modal value' of 68 inches, and 

 would rise again steeply to the exceptionally tall 

 men at the upper end of the row. [13] l 



A more instructive method of graphically repre- 



1 For references see the end of the Volume. 



