THE MAGIC INVERSION.
Join two square parallel ends by a third piece, half an inch broad and an inch and a half long, using a piece of cardboard doubled up, with that interval between, as the simplest material. In the middle of one end make a round hole, a little more than one-twelfth of an inch wide, and in the centre of it fix the head of a pin or point of a needle. Directly opposite, in the other side, make a large pinhole. If the latter is held to a strong light, and the eye is applied to the other hole, the head of the pin will be seen, not only greatly magnified, but turned upside down.