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 document 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 document, 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 document 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 constitution and
color and ink.

See illustrations of various kinds of handwriting at end of this book.




CHAPTER XV