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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 XIII 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.

L Inner or Radial side

0. Outer or Ulnar side





from both sides

from neither side

from both sides

I and 0 both absent

I and 0 both present

upper supply from


I side
















from t side

from I side

from 0 side

from 0 side



I absent

0 absent








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.

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