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
saturated with alcohol, for the purpose of bringing out as yellow
rusty marks all the pen strokes which had not been entirely removed by
erasure.

This treatment fixes the appearance of the spread lines and colored
spots in the space that has been washed and renders more noticeable
the stain caused by a partial sizing. In this manner apparently white
paper on which at first no traces of characters could be found showed
a yellow tinge, denoting the presence of previous writing, and on the
application of gallic acid and an infusion of nut-galls became
sufficiently distinct to permit the erasure and forgery to be
detected.

When an erasure is made on the surface of such a paper, the mineral
and organic materials of the sizing and loading are removed, and the
fibres of the paper which they unite are deranged in form and
position. Such a surface exhibits invariably the teased-up ends of the
fibres, and generally shows by the agreement in their direction in
what way the scratching was done.

Even in cases where a substitute for the sizing has been so
successfully added that no change in color or surface is observable,
the fibres will show by their unusual positions that they have been
disturbed. When an attempt has been made to write over the place
without sufficiently restoring the sizing, the effects can be seen in
the running of the ink between the fibres and the staining of the body
of the paper to a considerable depth from the surface and to a
considerable distance from the spot.