112 Life and Letters of Francis Galton 



and social influences, education, money, leisure, and surroundings that en- 

 courage work or idleness") in the same way. Galton then assumes that if 

 S be the measure of success, A of ability and C of circumstance,* 



and he then points out that the regression of success on ability will be just 

 one half, if ability and circumstance be uncorrelated. But I see absolutely 

 no reason for assuming the above form of relation between Success, Ability 

 and Circumstancef . 



Galton considers the intensity of the relationship of Ability to Environment 

 at some length. He suggests that "a bright attractive boy receives more 

 favour, and thereby has more opportunities of getting on in life, than a dull 

 and unpleasing one, but these advantages are not without drawbacks; 

 attractiveness leads to social distractions, such as have ruined many promising 

 careers." Then he cites Henry Taylor's couplet: 



"Me, God's mercy spared from social snares with ease, 

 Saved by the gracious gift, ineptitude to please." 



But I fear that no generalities, only numerical observations, can lead us 

 to a true appreciation of the value of r AC . Researches since Galton's day 

 show how small is the correlation of Ability and Environment. Galton 

 suspected this and wrote that he believed home influences were much less 

 potent than might be supposed. Galton states that the result of his inquiry 

 was "to prove the existence of a small number of more or less isolated 

 hereditary centres, round which a large part of the total ability of the 

 nation is clustered, with a closeness that rapidly diminishes as the distance 

 of kinship from its centre increases." 



He further held that these exceptionally gifted families were an asset to 

 the nation. "It must suffice for the present to mention the existence of at 

 least nine gifted families connected with Fellows of the Royal Society, two 

 or three of whom are exceptionally gifted." He concludes (as he has done 

 elsewhere: see Vol. u, pp. 120-2) that it would be both feasible and advan- 

 tageous to make a register of gifted families. Such a register Galton started 

 for other fields of noteworthiness than the scientific, and fragments of this 

 boldly outlined scheme still lie in the archives of the Galton Laboratory. 



I have given considerable space to this paper of Galton, partly because 

 it forms the basis of the later book on Fellows of the Royal Society, but 



* The regression of success on ability would be J (a- A + <*c r Ac)l' T A-i where u A and <r a are the 

 variabilities and r AC the correlation of ability and circumstance. Clearly the regression of 

 success on both ability and circumstance = |, if r AC = 0. 



t Preserving the type of symbols used in the last footnote the better form of relationship 

 would be _ 



S-S = r 8A -r sc r A0 A -1 + r 8C - r SA r AC C-C 



<*S 1- ^AO ^A 1 — I^AC °"C 



where a bar denotes a mean value. Short of determining from actual observation the "three 

 correlations r SA , r sc , and r A0 , I do not see that we can profitably guess at values (such as i) 

 for the multiple regression coefficients. 



