The methods employed in judging the au thorship of handwriting by these and almost all later writers on the subject are the same as those relied upon by connoisseurs of paint ing. They deal exclusively with the pictorial and apparent peculiarities, and the undefined effect these produce upon the mind. The most daring of these methods is the so-called "Graphology,' described in a pamphlet of the Abbe Michon in 1880, which has many con scientious supporters and partial government recognition in Germany and France. This curious study has for its object the revelation of the character and peculiarities of a writer by his handwriting. It would lead to too long a digression should the various claims of the advocates of graphology be reviewed. It must suffice here to say that some of these, not con tent with finding in the manuscript of an un known writer personal peculiarities which he al ready possesses, have imagined they could de tect the lurking tendencies to virtuous or vicious deeds such as self-sacrifice, kleptomania, mur der, etc., which he has never developed. These are deduced from the pen habits which they think they detect in the writing: such as de liberation, precipitancy, economy of paper or of effect, etc., etc. M. Bertillon thinks "To the public no proof is so decisive as that of personal identification of individuality, yet how many mistakes are made?" He believes with the exception of the advance in photography the art of handwriting judgment is just where Raveneau left it in the reign of Louis XIV. He forgets the aid he himself has rendered to the art of differentiating and identifying hand writing by the application of his anthropomet rical measures for the identification of crimi nals. The former art without such methods is in precisely the state in which Bertillon found the latter before his demonstration that exact measurements of different parts of the body and the relation to each other of the results of such measurements entirely removed the chance of error in identification, whereas there have been many instances of mistaken identity, or denial of identity by a wife or other near rela tive of the person in question. The history of this minute branch of research resembles that of other and larger branches. Subjective im pressions such as those supplied by the feelings, indicating supposed relative amounts or inten sities of emotions or sensibility, which were the only guides to the pioneers of inductive re search, wave way to exact methods by employ ment of instruments of precision recording facts in intelligible units, in estimating, for example, degrees of acidity, pitch of sounds, height of temperatures, intensity of lights. One after the -other the old subjects of research were fur nished with these unequivocal means of record ing phenomena, and all the new subjects were required to find such means or forfeit recogni tion. Thus through mathematics astronomy, already in the van of exact sciences, was en abled to make enormous enlargements of our view of the universe in the last two centuries, and even those objects of research which seemed to defy such treatment were provided with mathematical methods. Psychology be came a science admitting experimentation of which the results can be expressed in units, and chemistry is becoming as loyal a subject of that science of relation — mathematics — as its sis ters, physics and mechanics.
The purpose of the investigation of a hand writing will determine the kind of examination that is made. If the object be to ascertain whether a particular signature has been legiti mately placed as an authentification of a writ ing, it is necessary to scrutinize the paper on which it is written for evidence of scratching, erasing or other tampering; the ink for peculiarities of constitution which may be in consistent with its use at that time and in that place. The question of superposition of lines may show that the writing it validates was made after the signature. In numerous crimi nal trials each of these and of many other un mentioned demonstrable facts have at once stamped documents as fraudulent and obviated the necessity of the more particular study of the character of the writing. (Thus a water mark in a paper on which was written a state ment bearing date 1868 represented the Ger man Eagle which was not adopted till after 1870, and this of course showed the whole in strument to be a fraud. A similar conclusion is
forced in the Lase of traced characters purport ing to have been written before Hofmann's dis covery of the aniline colors yet demonstrably produced by aniline ink). The value of a sig nature as authenticating a contract is forfeited if it is clear that parts of the body of the docu ment were written after the signature was writ ten. These and other problems in the domain of plassopheny are too numerous to treat in this place and attention will be directed ex clusively to the grounds for deciding two speci mens of writing to be by the same or by dif ferent hands.
The first and most obvious method is to compare their respective features: large or fine writing; perfect or imperfect shaping of the letters; slant or angle of the stems and tails of letters with the line of writing; peculiarities (of which there are always a number) in the forms of individual letters or in the manner of connecting or grouping them; alterations in pressure producing shading in certain direc tions, and many other similar details. These peculiarities are pictorial. In all genuine writ ing they arise from the limitations of the writer, first in forming a mental picture of what he wants to produce, and secondly in producing it. Any one of these peculiarities can be easily imitated by another, and indeed all the visible details together can be drawn or traced by a skilful artist, yet in the latter case not without revealing to one using a magnifying glass that the lines have been slowly and carefully drawn and not dashed off with ease. Even if words ate photographed or traced from an original and afterward inked, an ordinary magnifying glass will show a difference in the pen marks from the current facility of the original writer. The careful .study of such details constituted the entire basis of judgment of the expert till within recent years, and usually they will suffice; for though the forger should know all the minute peculiarities which are disclosed to the patient study of a handwriting, yet he could not reproduce many of them without betraying in the result a painstaking, labored use of the pen which would excite suspicion. Where the same word or signature occurs twice or more in a document the forger must avoid exact repetition of all the minutia and at the same time not make such deviations as are inconsist ent with the habits of the writer. The most important of these habits for purposes of identi fication are not pictorial nor immediately ap parent to the eye.
Among the most important kinds of characteristics which insensibly influ ence the judgment in forming a conclusion as to identity of authorship of two specimens of handwriting are the proportions between cer tain parts of a letter, or word, or group of these, which often occur together. Especially is this the case with a signature, which is writ ten so frequently that the act becomes almost automatic and therefore one in which the peculiarities due .to the hand and arm making it, and to the brain furnishing the pattern, are most prominent because without the interfer ence of voluntary effort. The result in fact re sembles typewriting where the defects in the levers and type-faces of a typewriting machine can be detected; but with this difference that in handwriting they are still recognizable even when from lack of space or other causes the signature is written smaller or larger than usual. In such cases there is found a greater con formity to the established relations of parts of the signature than any foreign hand could make without a pantograph or other artificial aid. These proportions of parts may be detected either individually by carefully noted measure ments, or by composite photographs of genuine signatures. Each method has some advantages over the other. In employing composite photog raphy one attains to an ideal signature be cause all the possible characteristics of relation in every signature have been introduced, but on the other hand by this means only a form has been evolved — a graphic average — which must then be made the standard for comparison.