“This subject is of practical importance, in which the value of the microscope has again and again been demonstrated. On several occasions have we been enabled to clear the path for justice to ferret out the work of the contract falsifier, and shield the innocent from the unjust accusations of interested rogues. The range of observations in investigations of written documents with the microscope is a broad one. We may begin with the characteristics of the paper upon which the writing is made, which may enable us to ascertain many facts of importance; for instance, a great similarity might indicate, with associated facts, that the documents were prepared at about the same time. A marked dissimilarity might also have an important bearing upon the case. The difference of the paper may exist in the character of the fibres composing it, the finish of the paper whether rough or smooth, the thickness, modifying the transmissibility of light, the color, all of which may be ascertained with the microscope.

“The ink used in the writing may then be examined. If additions have been made to the document within a reasonable time of its making, microscopic examination will in all probability demonstrate the difference by keeping the following facts in view: Some inks in drying assume a dull, or shining surface; if in sufficient quantity, the surface may become cracked, presenting, when magnified, an appearance quite similar, but of a different color, to that of the dried bottom of a clayey pond after the sun has baked it for a few days. The manner in which the ink is distributed upon the paper, whether it forms an even border, or spreads out to some extent, is a factor which may be also noted. The color of the ink by transmitted or reflected illumination is also a very important factor. This in one case which I had in hand proved of great importance and demonstrated the addition of certain words which completely annulled the value of the document in a case involving several thousand dollars. And in a certain case where the lines of a certain document were written over with the idea of entirely covering the first written words, the different colors of the inks could not be concealed from the magnified image as seen under reasonably low powers of the microscope.”

The value of the microscope in this field of research is so great and the facts elicited by it so vital, I wish to emphasize its practical utility as strongly as possible. Of course the principal object in such an examination of written or printed documents is the erasures or additions; then the coloring of different inks applied and the mode of their execution. As to erasures, this can be accomplished in two ways, either by the use of a penknife or by a chemical preparation. The former is the one most commonly resorted to, and is effected in the following manner. With a well sharpened knife blade the surface of the paper is carefully scraped until all objectionable lettering and wording appear to the naked eye to have been effaced; but under a microscopical examination the impression made by the strokes of the pen may easily be detected, while the different colors of the inks are still plainly visible under the microscope.

The second method is by the application of a chemical preparation by which the ink is made soluble and is then easily removed from the paper by means of a blotter or absorbent cotton. Of course this method is also an imperfect one and the letters can easily be traced by close observation. When a chemical preparation has been used for erasing purposes, I find that in most cases it leaves a stain and also that the fibres of the paper are more or less destroyed by the chemical used; thus always leaving evidence that the document has been tampered with.

George E. Fell in his excellent paper says: “The eye of the individual making the erasures is certainly not sufficient, and even with the aid of a hand magnifier, the object might not be effectually accomplished. We will find that the detection of an erasure made by the knife is a very simple matter and may be detected by the novice. An investigation may be made by simply holding the document before a strong light and this is usually all that is necessary to demonstrate the existence of an erasure of any consequence.

“This is, however, a very different matter from making out the outlines of a word or detecting the general arrangement of the fibres of the paper, so as to be able to state whether writing has been executed on certain parts of the document; and again, when we enter into the minutiæ of the subject, we will find that the compound microscope will give us results not to be obtained by the simple hand magnifier.”

On several occasions I have had the opportunity for demonstrating with the microscope additions made to certain documents, two of which were wills (testaments); these additions were made in the following manner:—First an erasure was made and then the additional matter written over the erasure. With the microscope I could at once detect the erasure beneath the addition; also the different colors of the inks. Then, and this is the most important result of the microscopical examination, by close observation, I could discern the strokes of the pen in the original lettering as well as those of the additional lettering, and finally the general mode of their execution.

In regard to the examination of legal documents, United States currency, printed and written matter, mutilated documents, including forgeries, etc., from a legal point of view (as to their genuineness), it will suffice to say that the principal features are, as already stated, first, the detection of erasures and additions; second, the comparison of the colors of the different inks used in the original and in the additional lettering, and finally the mode of their execution. This includes of course a careful observation of the original writing as to the general and comparative expression. In the observation of the characteristics of the letters constituting the document, I will call attention especially to the shading and general formation of the letters, that is, the stroke of the pen either in a downward or upward movement. This comparison includes both capital and small letters and even punctuation.

All these things, as well as the grammatical and orthographical relationship and comparative differentiations, must be taken into consideration in order to enable the microscopical examiner to give a positive opinion.

A microscopical examination of paper documents, such as wills, notes, checks, etc., as to whether or not they have been mutilated or forged, is certainly the most reliable test, and by far the easiest and simplest method of determining the authenticity or spuriousness of a document. An expert microscopist and observer can at once arrive at a correct and positive conclusion as to the genuineness of an autograph.