Part 9 (2/2)
Chevallier and La.s.saigne experimented together on the effect produced by the vapor of iodine on the surface of the papers or doc.u.ments upon which the alteration of writing was suspected. Take a bottle with a wide mouth from ten to eleven centimeters in height, and the opening from five to six centimeters in width. This last is covered by a disk of unpolished gla.s.s. Into the bottom of this vessel introduce from twenty to thirty grams of iodine in crystals.
Place the portion of paper on which the vapor of iodine is to act at the opening of the bottle, and cover it with the stopper of unpolished gla.s.s, on which put a weight so as to exert a slight pressure, and in order that the aperture may be hermetically closed. Then allow the vapor of iodine to act on the dry paper for three or four minutes at the temperature of 15 to 16 C. and examine it attentively. When the surface has not been spotted by any liquid (water, alcohol, salt water, vinegar, saliva, tears, urine acids, acid salts, or alkalis) a uniform pale-yellow or yellowish-brown tinge will be noticed on all parts of the paper exposed to the vapor of iodine.
Otherwise a different and easily distinguished tinge shows itself on the surface that has been moistened and then dried in the open air.
Machine-made papers with starchy and resinous sizing give such decided reactions that sometimes it is possible to distinguish by the color the portion of the paper treated with alcohol from that moistened with water. The spot produced by alcohol takes a kind of yellow tinge; that formed by water becomes a violet blue, more or less deep, after having dried at an ordinary temperature. As to the spots produced by other aqueous liquids, they approach in appearance, though not in intensity, those occasioned by pure water. Feeble acids, or those diluted by water, act like water; but the concentrated mineral acids, in altering more or less the substance of the sizing, produce spots that present differences.
Spots which become apparent by using vapor of iodine are due to chemical agents whose strength has altered either the fibers of the surface, or the paste uniting them.
In a word, the test of a doc.u.ment or paper by vapor of iodine has the double advantage of indicating the place of the supposed alteration and operating afterwards with appropriate reagents to bring back the traces of ink. It is only the reappearance of former letters or figures written or effaced that demonstrates forgery. Much time may be profitably spent in merely scanning each letter of a doc.u.ment, and the writing by lines, paragraphs, and pages before a closer scrutiny.
Gradually, if the writing be genuine, its character will begin to reveal itself, and unconsciously a hypothesis as to the physical causes of the irregularities or characteristics will be formed.
When an entire doc.u.ment or page is forged, the ornamentation, flourishes, or the capitals at its head will often be seen to be out of keeping, either with its nature or with the supposed author's habits in similar cases. In a writing all must agree, place, day, year, handwriting, superscription or heading, signature, and material carrying the writing, especially paper, both as to const.i.tution and color and ink.
See ill.u.s.trations of various kinds of handwriting at end of this book.
CHAPTER XV
GUIDED HANDWRITING AND METHOD USED
The Most Frequent and Dangerous Method of Forgery--How to Detect a Guided Signature--What Guided Handwriting Is and How It Is Done--Character of Such Writing--Writing by a Guided Hand--Difficulty in Writing--Force Exercised by Joint Hands--A Hand More or Less Pa.s.sive--Work of the Controlling Hand--How Guided Writing Appears--Two Writers Acting in Opposition--Distorted Writing--How a Legitimate Guided Hand is Directed and Supported--Pen Motion Necessary to Produce Same--Influence in Guiding a Stronger Hand--Avoiding an Unnatural and Cramped Position--Effect of the Brain on Guided Hand--Separating Characteristics From Guided Joint Signature--Detecting Writing by a System of Measurement.
Guided handwriting is one of the most frequent means of forgery and oftentimes the most difficult to detect. It has been established that with care the elements of each handwriting can be detected and proven in a guided signature. The leading handwriting experts of the world are unanimous in declaring that it is possible for holding another's hand in making a guided signature to infuse the character of the guider's hand into the writing.
Guided handwriting is the writing produced by two hands conjointly and is usually erratic, and at first sight, hard to connect with the handwriting of any one person.
The character and quality of writing in case of a controlled or a.s.sisted hand must depend largely upon the relative force, exercised by the joint hands. The difficulty in writing arises from the antagonizing motion of one hand upon the other, which is likely to produce an unintelligible scrawl, having little or none of the habitual characteristics of either hand.
Where one hand is more or less pa.s.sive, the controlling hand doing the writing, its characteristics may be more or less manifest in the writing. But obviously the controlling hand must be seriously obstructed in its motions by even a pa.s.sive hand; and since the controlling hand can have no proper or customary rest, the motion must be from the shoulder and with the whole arm. The writing will therefore be upon an enlarged scale, loose, sprawling, and can have little, if any, characteristic resemblance to the natural and habitual style of the controlling writer, and of course none of the person's whose hand is pa.s.sive.
In appearance it changes abruptly from very high or very wide to very low or narrow letters. This is to be explained by the non-agreement in phase of the impulses due to each of the two writers. If both are endeavoring at the same moment to write a given stroke the length of that stroke will be measured by the sum of the impulses given by the two writers. If they act in opposition to one another, one seeking to make a down stroke while the other is trying to make an up stroke, the result will be a line equal to the difference between the stronger and the weaker force.
As these coincidences and oppositions occur at irregular but not infrequent intervals, like the interference and amplification phases of light and sound waves, the result traced on the paper might be expected in advance to be--and in fact is--a distorted writing where maxima and minima of effect are connected together by longer or shorter lines of ordinary writing.
The only state of things which can justify the guiding of a hand executing a legal instrument is the feebleness or illness of its owner.
When such a.s.sistance is required it is usually given by pa.s.sing the arm around the body of the invalid and supporting the writing hand while the necessary characters are being made.
Both partic.i.p.ants in this action are looking at the writing, and both are thinking of the next letter which must be written, and of the motion of the pen necessary to produce it. Unless the executing hand were absolutely lifeless or entirely devoid of power, it would be impossible for it not to influence the guiding and presumably stronger hand; for the least force exerted cannot fail to deflect a hand, however strong, in an unnatural and cramped position. Nor can the hand of the guider fail to add its contribution to the joint effort, however much the brain which controls it may strive to render the hand entirely pa.s.sive. Both minds are busy with the same act, and insensibly both hands will write the same letter with the results just described.
Can the characteristics of each hand be separated from those of the other and the relative amount of the two contributions to the joint signature be stated?
This is a question which is naturally asked during the trial of a case involving the consideration of a guided hand. From the comparatively small number of experiments made in this direction it would be too hazardous to answer it in the affirmative, but it may be said that some of the characteristics of each hand can usually be made apparent by the system of measurement, and the indications seem to point to the probability of being able to increase the number of characteristics elicited in proportion to the number of observations made. If the significance of every part of every stroke could be properly interpreted, it follows that a complete separation of characteristics would be effected, but this would require an indefinitely large number of observations to be made and a quite unattainable skill in explaining them.
See specimens of guided signatures in Appendix.
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