Photographic /{esearche^ aiul Portraiture 333 



Apart from the (juestion, however, of whether the eye does pa>« under 

 review and uscertjuii tlie !i|i|)!Ufnt identity of all these jn8t-di.stiii<;niHhuhle 

 plots, we may unk what would happen to the rel.itivi- mc.isiirtiiHnt in tin* 

 following cases: 



A. AH the plots are absolutely alike except a It-w wluc^^ are extremely 

 different, say two iileiitical twins one oidy with a mole on tli<' ('i''- 



li. All the plots are different hut not widely diflerent. 



Tlie comparates in case li would present a hiffher index of mi.stakal>ility 

 than those in A, fur we should liave in the aise of .1 to proceed with dis- 

 tancing the comparates until the isolated anomalous feature disappeared. It 

 might be nothing of course so easily observed and allowed for jus a mole, but 

 the measure seems largely to depend upon items of extreme divergence rather 

 than on an avenige of all comparable plots. 



Nevertheless the whole investigation is of great suggestivenass, and its 

 originality striking for a man of Galton's then age. He sjiw a great need, 

 and he did his best to supply it, spending a large part of many years over 

 the problem. If he did not fully solve it, no one has done so much towards 

 its solution, and no one to this day hivs tested his work, his apparatus or 

 his method and iiscertained how far they would carry us. 



"The niensureinent of Resemblance is of wider importance than may appear at first sight. It 

 covers a field of research that escai^s the ordinary measurements by foot rule, scales and watch. 

 It is particularly applicai>le to a variety of biological studies in which hereditary likenesses and 

 family or racial jwculiarities are inquired into, and seems eminently suitable for comparing 

 conipo.site photographs. The account of the nieth(xl I propose has been given merely in outline. 

 It presents many side-issues of interest, and deserves a large amount of photograpliic illustration 

 such as I am now unable to give." 



Thus wrote the veteran of 84 ! What is needed is that some one should 

 take up the subject where Galton was forced to leave it, starting |X).ssibly 

 with his material and apparatus. What are the average degrees of resemblance 

 of parent and child, of brothers and sisters, of first cousins, etc.? And would 

 the results obtained from Galton's Index of Mistakability correspond with 

 those found by the principle of con-elation from a single character in kinsmen 

 of various degrees ? 



The number of years over which Galton's photographic researches are 

 stretched is in itself remarkable, but more remarkable still is the amount 

 of time in those years he devoted to them. I have spent weeks in going 

 through his manuscripts, his published papers, his photographic apparatus, 

 his negatives and his prints, with the view of writing the account in this 

 chapter, but it is more than possible that I have missed points of interest in the 

 overwhelming mass of his material. The suggestiveness of his contributions 

 to portraiture seems to me great, but long as he lived he had only time to 

 blaze the trail. In heredity and statistics a younger generation has been found 

 to take up his work; in photography and portraiture his pioneer steps have 

 not yet been trodden into a well-marked track by enthusiastic disciples. 



