“There is an increasing use of the typewriting machine for the production of spurious papers,” he began, rattling the note significantly. “It is partly due to the great increase in the use of the typewriter generally, but more than all is it due to the erroneous idea that fraudulent typewriting cannot be detected. The fact is that the typewriter is perhaps a worse means of concealing identity than is disguised handwriting. It does not afford the effective protection to the criminal that is supposed. On the contrary, the typewriting of a fraudulent document may be the direct means by which it can be traced to its source. First we have to determine what kind of machine a certain piece of writing was done with, then what particular machine.”
He paused and indicated a number of little instruments on the table.
“For example,” he resumed, “the Lovibond tintometer tells me its story of the colour of the ink used in the ribbon of the machine that wrote this note as well as several standard specimens which I have been able to obtain from three machines on which it might have been written.
“That leads me to speak of the quality of the paper in this half-sheet that was found on Mr. Maitland. Sometimes such a half-sheet may be mated with the other half from which it was torn as accurately as if the act were performed before your eyes. There was no such good fortune in this case, but by measurements made by the vernier micrometer caliper I have found the precise thickness of several samples of paper as compared to that of the suicide note. I need hardly add that in thickness and quality, as well as in the tint of the ribbon, the note points to person as the author.”
No one moved.
“And there are other proofs—unescapable,” Kennedy hurried on. “For instance, I have counted the number of threads to the inch in the ribbon, as shown by the letters of this note. That also corresponds to the number in one of the three ribbons.”
Kennedy laid down a glass plate peculiarly ruled in little squares.
“This,” he explained, “is an alignment test plate, through which can be studied accurately the spacing and alignment of typewritten characters. There are in this pica type ten to the inch horizontally and six to the inch vertically. That is usual. Perhaps you are not acquainted with the fact that typewritten characters are in line both ways, horizontally and vertically. There are nine possible positions for each character which may be assumed with reference to one of these little standard squares of the test plate. You cannot fail to appreciate what an immense impossibility there is that one machine should duplicate the variations out of the true which the microscope detects for several characters on another.
“Not only that, but the faces of many letters inevitably become broken, worn, battered, as well as out of alignment, or slightly shifted in their position on the type bar. The type faces are not flat, but a little concave to conform to the roller. There are thousands of possible divergences, scars, and deformities in each machine.
“Such being the case,” he concluded, “typewriting has an individuality like that of the Bertillon system, finger-prints, or the portrait parle.”