88 STANDARD OF COMPARISON. 



the age of puberty being considerably affected by temperature, these 

 countries present an exceptional condition which is not applicable 

 to America and Europe in general. I shall therefore ignore them 

 and make my comparison more particularly with Ireland and Scot- 

 land. I can do this better because the statistics for these last men- 

 tioned countries are more complete and reliable than for Finland 

 and Sweden. The following table giving the ages of mothers for 

 different percentage of children, shows that while the Redfield 

 mothers of the eighteenth century began reproduction a little earlier 

 than the Scotch mothers of the middle of the nineteenth century, 

 the average age of reproduction was higher and was continued to 

 a later age. In other words, the standard here adopted is somewhat 

 high as compared to Scotland, and markedly high as compared to 

 Ireland, and consequently it will operate against, rather than in 

 favor of, the theory that eminent men should, as a whole, have birth- 

 ranks above the average. 



TABLE III. 



AGES OF MOTHERS FOR DIFFERENT PERCENTAGES OF CHILDREN. 



Proportion of children. Redfields. Scotland. Ireland. 



10 per cent under 22-0 22-4 21-2 



50 per cent under 29-2 28-11 27-3 



90 per cent under 39- 10 39-6 35-0 



TEST BY INSURANCE RECORDS. 



The above comparisons have been made with different classes 

 of mothers because the statistics were in a form that would enable 

 me to do so, but I am able also to make a comparison between 

 American fathers of the eighteenth century and Irish, fathers from 

 1830 to 1841. Prof. Miles quotes from Walford's Insurance 



