150   Life and Letters of Francis Galton

1895 that he was prepared with his full ideas of indexing by finger-prints alone*. He was clearly in doubt in 1893-because his own scheme of indexing was not yet fully developed-as to whether a population of 30,000 to 50,000 could be adequately indexed solely on their finger-prints, and because the Committee shared his doubts, it is a misrepresentation to assert that they condemned his work f. In his evidence he exaggerated nothing, and placed his methods and their difficulties frankly before the Committee. It is idle to say either that Galton failed to get an independent system of finger-printing carried, or that the Committee condemned his system. Fingerprinting was destined to become wholly independent of bertillonage; it very soon did become so, as the study of finger-prints advanced, but in 1893 no one had published a complete system of indexing, and Galton was the only man who was able to make even suggestions in this matter. Above all to this day the all-important problem of indexing single prints seems to be unsolved I. The Committee laid down the following three main conditions for deciding what system should be adopted

"(1) The descriptions, measurements or marks, which are the basis of the system, must be such as can be taken readily and with sufficient accuracy by prison warders or police officers of ordinary intelligence.

"(2) The classification of the descriptions must be such that on the arrest of an old offender who gives a false name his record may be found readily and with certainty.

"(3) When the case has been found among the classified descriptions, it is desirable that convincing evidence of identity should be afforded."

Applying these conditions to galtonage, the Committee reported that

"The 1st and 3rd of these conditions are met completely by Mr Galton's finger-print method. The taking of finger-prints is an easy mechanical process which with very short instruction could be performed by any prison warder. While" in M. Bertillon's system a margin greater or less has always to be allowed for errors on the part of the operator, no such allowance has to be made in Mr Galton's. Finger-prints are an absolute impression taken directly from the body itself; if a print be taken at all it must necessarily be correct. While the working of this system would require a person of special skill and training at headquarters, it would have the enormous advantage of requiring no special skill or knowledge on the part of the operators in the prison§, who would merely forward to headquarters an actual impression taken mechanically from the hand of the prisoner. With regard to the third condition again, as we have already pointed out, Mr Galton's system affords ample material for conclusive proofs of identity....

"The Committee were so much impressed by the excellence of Mr Galton's system in completely answering these conditions that they would have been glad if, going beyond Mr Calton's own suggestion1j, they could have adopted his system as the sole basis of identification." (p. 29.)

* See later our account of his Finger Print Directories, 1895.

t Dr Faulds, loc. cit. p. 41, "Mr Galton's own system, afterwards expounded in a work

[i.e. his Finger-Prints of 1892 abounding in grave errors and set forth in a way which the

Blue Book of 1894 characterises." Cf. our pp. 145-147.

$ Suppose a single print is found after a burglary and we need to ascertain whether the burglar was a known criminal, i.e. on the finger-print record. We may not even know of which finger it is a print, and yet the single print is perfectly individual and would identify the culprit were we able to index our single prints.

§ I have examined the finger-prints on many hundreds of practice sheets of prison warders, and can certify that this statement has been amply confirmed by experience.

II Italicised by biographer. The whole essence of the Report was the abandonment of Bertillon's " distinguishing marks," the use of his system as merely a method of indexing, and the ultimate identification by the finger-prints (see p. 20).