THE PENETRATIVE EYEGLASS.
Perhaps some one in the company has made use of the saying that he “can see as far through a millstone as anybody.”
Eagerly espouse his cause, and declare him, indeed, gifted with preternatural vision, as you will prove to him by your magic spyglass.
A box is made with two upright extensions, in which are placed the tubes of telescopes, with plain glass eyepieces. A A A A are plane mirrors, set all at an angle of 45 degrees, so that any one looking in at either end, sees whatever is visible at the other extremity.
Fig. 137.