104 Life and Letters of Franeix (iulton 



and 1 know from the personal accounts of botli, how these two men, in many 

 respects of kindretl mind, appreciated each other. And secondly, l)ecau8e 

 Galton endeavoured to destroy dogmas about muscle, so similar to those held 

 by many about bniin. 



"No one doubts that muscle is hcrtKlitary in horses and dogs, but humankind are so blind 

 to faoU and so governed by prt-cdnceptions, tlmt I \\i\vv heiinl it fr»'(|u<'ntly iisscrted that muscle 

 is not herwlitary in men. (Jarsmen and wrestlers have miiintained that their lieriK's spring up 

 capriciously, so I have thought it advisable to make inquiries into the matt«r. The results I 

 have obtained will beat down another place of refuge for those who insist that each man is an 

 independent creation, and not a mere function, physically, morally and intellectuaJly, of ancestral 

 qualities, and external influences." (p. 305.) 



We must now turn to Galton's final summarising chapters. I must con- 

 fess frankly that while I consider that Galton has demonstrated the hereditary 

 character of ability as judged by eminence, I Hud it very hard to fit in 

 his statistical results with our present knowledge of the inheritance of 

 ability. 



One thing of course follows certainly and cojiclusively from the data, 

 namely the farther removed, either directly or collaterally, a kinsman is from 

 his eminent relative the smaller is his chance of being eminent. A son has 

 the best chance of all and then comes the brother, and the probability tails 

 away as we come to more distant relatives. This is reasonable because the 

 ability has been usually diluted by what Galton would term 'mongrel' 

 marriages, i.e. marriages with the intellectually mediocre. But there are two 

 great difficidties in my mind about the analysis. The first is that of his 

 grade of ability. On pp. 33-34, he defines his conception of eminence to be 

 250 men per million or one man in 4000. He also assumes a normal distri- 

 bution for intelligence. Now, I think, that the student of Hereditary Genius, 

 who considers the men, whether Judges, or Statesmen, or Men of Science, 

 and still more the Divines, in Galton s lists, will hardly credit them with 

 this degree of rarity. I confess that limiting the selection to the class of 

 men educated professionally or by class tradition to aim at distinctions of 

 this kind, I felt in my recent re-perusal that 1 in 500 was an adequate 

 measure of the eminence, and before I came to the end of the book, I doubted 

 whether it was more than 1 in 100. That is to say that while some of 

 Galton's lists indicated men with a grade of 1 in 10,000 or even more, there 

 was a very considerable tail, some of whom had not a greater ability than 

 you would find in one in a hundred or even fewer. 



1 now started to test this on Galton's hypothesis that the distribution 

 of capacity is normal, and on the result of mucl» recent work that in a 

 stable population the son will on the average inherit half his father's devia- 

 tion from mediocrity', the mothers not being seleeted. In this manner I was 

 able to form the following tables which indicate in a population of a inillion 

 the probable number of eminent sons of eminent fathers for each standard of 

 eminence. 



' Id technical language, if the standard deviations of the |.<i|,iil.itiiiii in tin' iivi. L'eiwnitunis 

 arc equal, the co^'tficietit of a>rrelatiou will be Q-T>. 



