MADDENING PUZZLES.

Pelorus Guardian and Miners' Advocate., Volume 22, Issue 93, 1 December 1911, Page 2

MADDENING PUZZLES.

STRANGE THINGS THAT MIRRORS SHOW US.

An old but none the less interesting and instructive problem asks : “Why does a mirror reverse right and left, but not up and down ?’’ Suppose, for instance, the word HAT were printed vertically thus : H A and held before a mirror, the imT

age would be like the original, and could be read quite easily ; but the H of the image would be at the top, as in the original. But if it were printed horizontally, as in a book, thus :—HAT, the mirror would reverse it and give it back as TAH. Hence a sign or book held up against a mirror cannot be read, because the words are all reversed, though the top and bottom of the book are not. The problem is to explain this anomaly. It is well to caution one not to work at it more than an hour a day, as it may drive some people near to insanity. While this problem may be old, perhaps the following curious version of it may be new to some :—When one corner of a room consists of two mirrors at right angles to each other, as is sometimes the case in restaurants or public halls, then the image seen in that corner is not reversed, either right and left or up and down ; a book held up in front of that corner can be read quite as easily as the original. If you offer to shake hands with your image in this corner, he will be as polite to you as you are to him, and will extend his right hand to you if you do so to him ; while in the plane mirror the image will follow the golden rule when you offer him your left hand, but not when you offer the right one.

Another curious feature which may be new to some, which is seen in this mirror corner, is that no matter what part of the room you are in, you can always see your image in the corner. If you run around in the room, you see your image always remaining in the corner. In this way, suggests Prof. Carl Herring, a moving body might be photographed as though stationary, on an opaque film, without right and left reversals. Possibly two such photographs of a moving object might, if skilfully taken, give curious effects when subsequently combined in a stereoscope. In the absence of such a mirrored room, the results can be obtained in a small way by means of a small frameless mirror or piece of mirror glass held perpendicularly against another mirror. They should, however, fit closely, and it la essential that they be held exactly at tight angles to each other.