A quantitative Study of Variation, Natural and Induced, etc. 201 
250—ı6a has great variability, and is inclined to break up into two 
distinct types, as witnessed by the bi-modal curves. 250—20a has but 
little variability and is decidedly uni-modal. The differences between 
these lines, and this tendency of 250—16a to break up into two types 
a i oo - + mn [0] nm \o fon a in oo - 
Me et. a ese 
Sma» S&S $ FS HB FH SE CS SRK 
Fig. 5. 
@o——_® = 250—I4a 
Ow = = — oO) = 250— 16a 
pm = 250— 208 
are more plainly shown by the use of correlation tables. Tables 13 
to 21 inclusive represent the facts. (See correlation tables page 216.) 
Notice that in each table that concerns 250—16a (tables 16, 17, 
and 18) there is a decided indication that the line tends to produce 
