as in the tint of the ribbon, the note points to one 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.
