_To guess, by smelling, which has been the Number struck out by a
Person in the Company, in the Product of a Multiplication given him
to do._
Propose to a person of the company to multiply, by whatever number
he pleases, one of the three sums which you will give him on a piece
of paper; desire him to strike out whatever figure he pleases of the
product of his multiplication, let him change and invert the order of
the remaining figures after the defalcation he has chosen.
While the person is making his calculation and the subsequent
operations, go in another room: when you are told you may return,
desire the person who has done the multiplication, to give you the
remaining product on a piece of paper or card; put it to your nose
as though you would smell it; then you will tell him, to the great
astonishment of the whole Company, what figure he had struck out.
In order to do this operation, first observe, that the figures
composing each of the three sums you propose to be multiplied, do not
exceed the number of 18.