As one means of determining whether the whole of a writing was executed at the same time, and with the same ink, or at different times, and with different inks, Mr. Peacock further says that the photographic process is very effective because it not only copies the forms of letters but takes notice of differences in the color of two inks which are inappreciable by the eye. He states that:
"Where there is the least particle of yellow present in a color, the photograph will take notice of the fact by making the picture blacker, just in proportion as the yellow predominates, so that a very light yellow will take a deep black. So any shade of green, or blue, or red, where there is an imperceptible amount of yellow, will pink by the photographic process more or less black, while either a red or blue varying to a purple, will show more or less paint as the case may be."
As to deception which the eye will not detect, in regard to the age of paper, he says:
"I have repeatedly examined papers which have been made to appear old by various methods, such as washing with coffee, with tobacco, and by being carried in the pocket, near the person, by being smoked or partially burned, and in various other ways. I have in my possession a paper which has passed the ordeal of many examinations by experts and others, which purports to be two hundred years old, and to have been saved from the Boston fire. The handwriting is a perfect fac-simile of that of Thomas Addington, the town clerk of Boston, two hundred years ago, and yet the paper is not over two years old."
The most remarkable case of deception to the eye, even when aided by magnifying glasses, is in determining when two pen strokes cross each other, which stroke was made first. Mr. Peacock does not explain how the deception is possible, but that it occurs as matter of fact, he shows by an account of a very decisive experiment. Taking ten different kinds of ink, most commonly on sale, he drew lines on a piece of paper in such a way as to produce a hundred points of crossing and so that a line drawn with each of ink passed both over and under all the lines drawn with the other inks. He, of course, knew, in respect to each point of crossing, which ink was first applied, but the appearance to the eye corresponded with the fact in only forty-three cases. In thirty-seven cases the appearance was contrary to the fact, and in the remaining cases the eye was unable to come to any decision.
By wetting another piece of paper with a liquid compound acting as a solvent of ink, and pressing it upon the paper marked with lines, a thin layer of ink was transferred to the wet paper, and that shown correctly which was the superposed ink at every one of the one hundred points of crossing.
Many cases have occurred, in signatures written with different inks, where some letters in one cross, some letters in another, in which it becomes important to decide the order of sequence in writing. It is also frequently important to decide the order of sequence in writing. It is also frequently important when the genuineness of an addition, as of a date, is the thing in dispute.
No subject can be more important or interesting to the business public or especially to bankers than that of the reliability of the lists of the genuineness of written papers. While it is true that in most cases there is some ear-mark beside the appearance of a signature, whereby to determine the genuineness of a document, it is also true that in many cases, and frequently in cases of great magnitude, payments are made on no other basis than the appearance of a writing. The most common class of these last cases is where "A" has been long known to be an endorser for "B," and where the connection between the two, which leads to the endorsements, is well known. There is nothing in the appearance in the market of a note of "B" endorsed by "A," that is, in any degree calculated to excite suspicion or to put a prospective purchaser upon his inquiry. If the endorsement of "A" resembles his usual handwriting, it is almost always accepted as genuine and if losses result from its proving to be counterfeit, they are set down to the score, not of imprudence, but of unavoidable misfortune.
Thus, as the ingenuity of rogues constantly takes new forms, the ways and means by which they can be baffled in these enterprises are constantly being multiplied. The telegraph and telephone give facilities for promptly verifying a signature where one is in doubt.
It happens not infrequently that the desire to get a given number of words into a definite space leads to an entirely unusual and foreign style of writing, in which the accustomed characteristics are so obscured or changed that only a systematic analysis can detect them. If there be no apparent reason for this appearance in lack of space, the cause may be the physical state of the writer or an attempt at simulation. If a sufficient number of genuine signatures are available, it can generally be determined which of these two explanations is the right one.