160 



Life and Letters of Francis Galton 



system of finger-print Identification Offices with a common nomenclature, 

 a common method of indexing and a common code. 



Realising how such Identification Offices, depending wholly on finger- 

 printing, now stretch from London to Tokyo, from Tokyo to San Francisco 

 and thence to New York, we see how Galton recognised a widespread need, 

 and how by his ceaseless energy he carried through a great reform. What- 

 ever influence his idea of correlation may have exercised in the field of 

 scientific investigation — and it has been indeed deep and far-reaching — the 

 establishment throughout the world of finger-print identification is a no less 

 astonishing mark of his power of achieving on the practical side. 



On October 16, 1902, Galton has still another letter in Nature (Vol. lxvi, 

 p. 606). It is entitled "Finger-Print Evidence." The problem he is concerned 

 with here is to find the best manner of convincing a judge and jury that an 

 accused person is really one whose finger-prints are already on the criminal 

 register. Owing to the courtesy of Scotland Yard he had received two 



Fig. 19. Ridgc-tracing Method of identifying Finger- Prints. 



enlarged photographs of thumb-prints. The first is that of an impression 

 left on the window frame of a house where a burglary had occurred, and the 

 second that of the left thumb of a criminal who had been released and whose 

 finger-prints were preserved and classified at Scotland Yard. Galton applies 

 the method of his Decipherment of Blurred Finger Prints (see our p. 194), 

 " believing that to be the readiest way of explaining to a judge and jury the 

 nature of the evidence to be submitted to them. ...The questions of the 

 best mode of submitting evidence and the amount of it that is reasonably 

 required to carry conviction deserve early consideration, for we may have a 

 great deal of it before long." In the accompanying diagrams it will be seen 

 that Galton has selected and numbered ten minutiae for identification and 

 comparison. It is scarcely conceivable that any twelve reasonably intelligent 

 men would fail to be convinced of the identity of the two thumb-prints, 

 although conviction would be still further strengthened were a third random 

 thumb-print of the same type presented, which would undoubtedly lack 

 corresponding minutiae. 



