The Multiplying Mirror.
This must be performed with a looking-glass made on purpose; the manner of making it is this:—First, make a hoop, or fillet of wood or horn, about the size of a half-dollar in circumference, and about a quarter of an inch in thickness. In the middle, fasten a bottom of wood or brass, and bore in it several small holes, about the size of peas; then open one side of this bottom, set in a piece of crystal-glass, and fasten it in the hoop close to the bottom. Take a quantity of quicksilver, and put as much into the hoop as will cover the bottom; then let into it another piece of crystal-glass, fitted to it; cement the sides, that the quicksilver may not run out, and the apparatus is complete. One side will reflect the beholder’s face as a common looking-glass; in the other it will be multiplied according to the number of holes in the wood or brass.