:28 



l*rof. Karl Pearson. 



also will be found to be taller than the brachy cephalic. Here we have 

 dealt with the correlation between shape of head and physique, the 

 correlation between absolute size of head and physique will be given 

 later. It would be of the greatest value to obtain the intensity of 

 correlation between shape of head and intellectual capacity. We hope 

 to return to this on another occasion.^ 



5. We may place here the variation results for pull and head index. 



VII. 



Sex. 



Organ. 



Mean. 



Standard 

 deviation. 



Coefficient 

 of variation. 



Female . . . 



"1 pull in f 



; lbs. t 



49 -220^0 -452 

 84 -016 ±0-270 



8 -217 ±0-320 

 12 -676 ±0-191 



16 -69 

 15 -09 





head index 



79 -572 ±0-064 



2 -999 ±0-044 



3-77 



(D). — On the Correlation of Fertility with Homogamy, 



6. In the reduction of my family measurements, I have been much 

 struck by the very high values obtained for the correlation in cha- 

 racters between husband and wife. For 1000 cases in which the stature 

 of husband and wife were determined, the correlation was nearly 0'3 ! 

 This is almost as close a resemblance as we have found for some cha- 

 racters between father and daughter. JSTow there is little doubt that 

 there is a certain amount of conscious assortative mating in this 

 respect ; a short man does not, as a rule, like a very tall wife. There 

 is further an unconscious mating arising from neighbours marrying; 

 neighbours in England often mean persons of the same local race, and 

 such local races differ considerably in their mean statures. f But my 

 data were very largely drawn from the professional classes, and in 

 large towns like London to marry "in the set" hardly means to marry 

 into the same local race. The parents, however, may in some cases 

 have come to London from the same locality. The question whether 

 husband and wife spring from the same rural district is one of con- 

 siderable interest, and deserves special investigation. I hardly believe, 

 however, that it will be found a source contributing much to the 

 intensity of assortative mating in my own data. A large proportion 

 ^of the data cards were filled in by members of the London professional 



* Measurements are now being made on brothers and sisters in schools, the 

 apparatus being provided by aid from the Grovernment Grrant. It will, however, 

 be some years before sufficient data have been collected. 



t Mr. Francis Galton has pointed out this source of indirect assortative mating 

 to me as worthy of consideratioPo 



