On a regular prescribed form impressions are taken so that the flexure of the last joint shall be at a given point on the record.
The digits are taken singly and then an imprint is made of all of them simultaneously.
When the prisoner has finished imprinting the record he is called upon for his signature, and immediately underneath the name, as written by himself, an imprint is left of the right forefinger.
For the edification of American police, Mr. Ferrier demonstrates that upon a sheet of paper you may sprinkle some charcoal dust and press it upon the paper with your thumb and then blow the dust off and the imprint of the digit will remain.
Most Positive Identification.
But this thumb print possibility in commercial papers has its greatest future in the positive identification which either thumb or finger print carries with it. Criminologists all over the world have satisfied themselves of the absolute accuracy of the finger print identification. It would be hard to figure just how many Constantines were arrested or kept under surveillance following the horrible murder in Chicago, the suspicions aroused by personal resemblances to the criminal's photograph and especially by the prominent gold tooth of the man. But in a criminal's finger print the merest novice anywhere in the world may take an ink impression of the fingers of the suspected criminal, and if these prints should be in the bureau of identification at Scotland Yard, with its 100,000 records of individuals, the man would be identified positively within half an hour—identified not only by the experts of the bureau, but an ordinary citizen would be an authority in attesting the proof.
This is a suggestion of the absolute accuracy of identifications on commercial paper. At the present time traveling salesmen who spend much money and who wish to carry as little as possible of cash with them, have an organized system by which their bankable paper may be cashed at hotels and business houses over the country.