Of cards which are “marked” as they come from the manufacturers there is
elsewhere mention. But it sometimes happens that the player cannot
understand the peculiar patterns of the back, and hence has to mark them
himself as he plays.
This is generally done, while he is holding them, by denting them with
the nail, scratching the edges or face, or bending the corners.
When the cards have backs perfectly white, the swindling manufacturer
can, at a moment’s glance, tell you what is on the face of the card; and
this secret he communicates to others, whom he employs to go out, and by
means of these cards to swindle people out of their money. This may seem
quite incredible to some; it is, nevertheless, done, and very
successfully too, and it is accomplished by embossing the paper on the
back, so as to form a small, fine grain, which the eye would take to be
the grain of the paper, this grain running different ways to represent
different cards. And there is only one position in which this card must
be held that it can be told; and that is, hold the end of the card that
is from you the highest, and then the shade will cast the grain in a way
that you can plainly see the marks.