inner by transmitted light. Even
to the touch the surface would reveal differences from the ordinary
condition of other parts of the paper.

But the forger usually endeavors to overcome these difficulties by
applying to the scratched area sandarach, resin, alum, paste, or two
or three of these together, the effect being to prevent an unusually
large flow of ink from the pen and its abnormal absorption by the
paper.

The paper should be placed between the observer and a strong light, by
which means, either with or without a magnifying-glass, a distinct
increase in the brightness of the suspected area may be noticed,
indicating a thinning, and even traces of letters, or marks which have
escaped the erasing-tool, may be seen.

A close scrutiny may show places where the surface has been partially
torn, and the fibres of the paper united together into little knobs,
and almost invariably a magnifying-glass will clearly show the
disturbance of the superficial fibres, as compared with other and
normal parts of the paper. If the latter be tinted, the change of
appearance may extend to color. The color of the paper should always
be attentively observed.

A change of color over the part which is the subject of investigation
may indicate the mechanical removal of the paper itself, or a washing
either with water or with acids, alkalies, or saline solutions. A
certain spotted character which follows this latter treatment differs
from the changes of color due to age or soiling.

When the heavier strokes--usually the down strokes--of a writing are
thicker and more blurred than usual a removal of sizing is indicated,
or an original imperfect sizing of the paper.

On the contrary, where the strokes are thinner and closer together
than usual, the cause is generally the application of resin, which has
been added, in all probability, to conceal a previous scratching of
the surface.

The spots produced by washing are more like penumbra, or blurred marks
bordering the tracings of the character, and are generally colored.

In order to bring out any traces of ink-marks which have been so far
removed as not to be observable by the naked eye, Coulier recommended
the placing of the document between sheets of white filter paper and
passing a hot flatiron over it, allowing the latter to remain on the
spotted parts for a short time. Another method is to wet the suspected
paper or document with alcohol, wrapped in another piece of paper also