180 



Life and Letters of Francis Galton 



that each print was about playing card size. Galton found that on repeated 

 trials he did not, by inspection only, deal these out into the same classes. The 

 same failure occurred when he selected standard types and endeavoured to 

 sort into groups by aid of these. Mere judgment by the unaided eye is liable 

 to be influenced by the intensity of inking of some ridges; two prints will not 

 always give the same extent of pattern. "A third cause of error is still more 

 serious; it is that patterns, especially those of a spiral form, may be apparently 

 similar yet fundamentally unlike, the unaided eye being frequently unable 

 to analyse them and to discern real differences" (p. 66). Accordingly Galton 

 introduced his system of "outlining" the pattern. To this we have already 

 referred in discussing his Phil. Trans, memoir (see our p. 164). His Plate 5, 

 here reproduced as our Plate X, shows samples of outlined patterns. Whether 

 it is needful for an expert always to outline is another question, but to become 

 an expert in classification, it is undoubtedly necessary to gain experience in 

 grouping by outlining, even if the classification is only to be in the broadest 

 categories. The chief reason for this is that the existing classification 

 schemes are in truth largely artificial. There is really no generic difference 

 between a "tented arch" and a "tented loop," or between an "eyeletted 

 loop" and a "small spiral in loop" which Galton reckons a whorl. There are 

 numerous such cases where the classification can only be by arbitrary 

 standardisation. We reproduce as our Plates XI, XII and XllI Galton's 

 Plates 7, 8 and 6 which will aid any reader desirous of learning to classify 

 by outlines; yet even then he will undoubtedly find rare patterns, which he 

 can only hope to thrust into a miscellaneous group of "composites." Galton's 

 Plates 9 and 10 (see our Plates XIV and XV) give threefold enlargements 

 of troublesome transitional patterns, the first between arches and loops and 

 the second between loops and whorls. The beginner should attempt to classify 

 them, and then compare his results with Galton's views on pp. 79-80. 



/. Inner or 

 Radial side 



from both sides 



/ and both absent. 



Spirals 



from / side 



above 



Rinds 



from neither side 



I and both present 



Loops 



from / side 



from side 



absent 



Duplex Spirals 



from both sides 



upper supply from 



I side 



side 



<£?v 



Spirals 



from side 



0. Outer or 

 Ulnar aide 



Fig. 32. It is necessary to suppose the finger-prints are from the right hand. 



On pp. 80-81 Galton repeats the classification of his Phil. Trans. 



