By way of illustrating one method of forgery interesting material which had played an important part in a court case was carefully examined.  It consisted of five or six graded photographic enlargements of the duplicate signature which were carefully examined with the aid of a microscope.  The original had been made by an elderly person and the forger had used the tracing process.  To the naked eye it appeared to be a capital copy; in fact, it seemed to bear every semblance of being genuine.  In the first enlargement of several diameters certain inaccuracies of tracing could be discerned, only, however, after attention had been called to them by an expert.  In the next enlargement these same errors were more apparent, and so on through the series.  The largest photograph was magnified several hundred diameters greater than the original and stretched across quite an area of paper.  From an examination of this largest one with a microscope it was evident that the forger first had traced his copy with pencil, afterward going over it with ink, but so irregularly had his pen followed the pencil lines that in certain portions of this enlargement there was room for a man’s fist between the first tracing and its inky covering.

In trying to detect forged handwriting every letter of the alphabet, wherever written, may be examined with a microscope for the following characteristics:  Size, shading, position relative to the horizontal line, inclination relative to the vertical line, sharpness of the curves and angles, proportion and relative position of the different parts, and elaboration or extension of the extremities.  In scarcely one of these particulars can a man make two letters so much alike that they cannot be distinguished by microscopical examination.

Although a great deal can be determined in a general way by close observation with the naked eye, it is always best to employ some magnifying power—­usually an ordinary hand lens or pocket magnifier will suffice—­but the writer has found it better to use a microscope objective of low power (four or five diameters), which is provided with an easily slipping sleeve, terminating in a diaphragm which cuts out the light entering the outside rim of the lens.  This sleeve may be pushed out for one or two centimeters, and the particular spot under examination isolated from the adjacent parts without undue magnification.  It is one of the popular fallacies that a high magnifying power is desirable in all cases of difficulty, but usually the reverse is the case in questions of handwriting.

Experts have sometimes impressed the jury with the fact that they had employed on some thick and opaque document, powers of several hundred diameters without the lately applied illumination from the side, reflected by a glass plate, introduced obliquely into the tube of the microscope.  Without such aid no microscopist need be told that the light would be wanting to illuminate the field under these circumstances.  The best authorities prescribe a magnifying power of not more than ten diameters for ordinary observation.  For special purposes higher powers are sometimes useful.  An ocular examination of the ink in the various parts of a written paper, document or instrument of any kind will generally decide whether it is the same.