ld be superfluous to have to remind intelligent and educated
persons that it is necessary for a collector of old documents to make
himself familiar with the peculiarities, habits and customs of the
period in whose literary curiosities he is dealing. Yet fact compels the
admission that extraordinary laxity and even ignorance exist on these
points. We are acquainted with a collector, by no means uneducated, who
gave a good price for a letter purporting to be by Sir Humphrey Davy,
the inventor of the miners' safety lamp, enclosed in an envelope. He was
ignorant of the fact that envelopes were unknown until 1840, thirty
years later than the date of this particular letter. Envelopes supposed
to have been addressed by Dickens have been offered for sale and
purchased, bearing postage stamps not in circulation at the period.

One would imagine that a forger would pay sufficient attention to his
materials to be on his guard against the blunder which earned the
perpetrator of the Whalley Will Forgery penal servitude. He put forward
a will dated 1862, written on paper bearing in a plain watermark the
date 1870! Another indiscreet person asked the Court to accept a will
written and signed with an aniline copying pencil, but dated years
before that instrument had been invented.

Both the works by Dr. Scott and Mr. Davies, given in the list, show
samples of watermarks of the various periods affected by forgers of
literary documents.

CHAPTER X.

INKS.

Examination for determining whether a writing has been done at one time,
or added to later, necessitates some acquaintance with the nature and
qualities of ink. In the ordinary case the assistance of a chemist is
necessary, but an enlarged photograph shows up minute differences with
amazing accuracy.

In the majority of instances alterations are made some time after the
original has been written, in which case a difference in the shade of
the ink will be perceptible, even to the unassisted eye. This is
particularly true when the now almost universal blue-black ink is used.

The period required for an addition to become as black as the older
writing depends very much upon the character of the paper. If this be
smooth and hard, and the writing has not been dried with blotting paper,
but allowed to dry naturally and slowly, it will become black much
quicker than if the paper be rough and of an absorbent nature.

A fairly reliable test is to touch a thick stroke of the sus