t with red lead. In this case you give
the person the choice of writing either with a black or red pencil;
and present him the proper side of the book accordingly.

_The Opaque Box made Transparent._

Make a box three or four inches long, and two or three wide, and have
a sort of perspective-glass, the bottom of which is the same size with
the box, and slides out, that you may privately place a paper on it.
The sides of this perspective are to be of glass, covered on the
inside with fine paper.

Let a person write on a slip of paper, putting your memorandum book
under it, as in the last amusement; then give him the little box, and
let him put what he has written into it. In the mean time you put the
memorandum book into the press, where the perspective is already
placed. Your assistant then takes the paper out of the book, and puts
it at the bottom of the perspective; which you presently take out of
the press, and direct the person to put the little box that contains
the paper under it. You then look in at the top of the perspective,
and feigning to see through the top of the box, you read what is
written on the paper at the bottom of the perspective.

With this perspective box you may perform another amusement, which is,
by having in a bag twelve or more ivory counters, numbered, which you
show to the company, that they may see all the numbers are different.
You tell a person to draw any one of them, and keep it close in his
hand. You then put the bag in the press, when your assistant examines
the counters, and sees which is wanting, and puts another of the same
number at the bottom of the perspective, which you then take out, and
placing the person's hand close to it, look in at the top, and
pretending to see through his hand, you name the number on the counter
in it.

_The Transposable Pieces._

Take two guineas and two shillings, and grind part of them away, on
one side only, so that they may be but half the common thickness; and
observe, that they must be quite thin at the edge; then rivet a guinea
and a shilling together. Lay one of these double pieces, with the
shilling upwards, on the palm of your hand, at the bottom of your
three first fingers, and lay the other piece with the guinea upwards
in the like manner, in the other hand. Let the company take notice in
which hand is the guinea, and in which is the shilling. Then as you
shut your hands, you naturally turn the pieces over, and when you open
th