glue, and rubbing it over with a burnisher. When thus treated it may be
again written over without difficulty. When erasures have been made
with acids, there is a removal of the gloss, or mill-finish; and there
is also more or less discoloration of the paper, which will vary
according to the kind of paper, ink, and acid used, and the skill with
which it has been applied. If the acid-treated surface is again written
over, the writing will present a more or less ragged and heavy
appearance, if the paper has not been first skillfully resized and
burnished. It is very seldom that writing can be changed by erasure so
as not to leave sufficient traces to lead to detection and
demonstration through a skillful examination.

Upon hard uncalendered paper erasures by acid when skillfully made are
not conspicuously manifest, nor when made upon any hard paper which
has been "wet down" for printing, since the luster upon the paper
would be thereby removed, and, so far as the surface of the paper is
concerned, there would be no further change from the application of
the acid. This applies to a wide range of printed blank business and
professional forms.

A forgery consists either in erasing from a document certain marks
which existed upon it, or in adding others not there originally, or in
both operations, of which the first mentioned is necessarily
antecedent to the last; as where one character or series of characters
is substituted for another.

The removal of characters from a paper is effected either by erasure
(seldom by pasting some opaque objects over the characters, painting
over them, or affixing a seal, wafer, etc., to the spot where they
existed) or by the use of chemical agents with the object of