The mirror below is one of the strangest objects I've ever seen. On the
back is a raised design, as shown, but the front is a bronze disc 7
centimeters in diameter, polished smooth and slightly convex, and it
reflects light just as a good mirror should. There appears to be nothing
unusual about it. But if you aim the mirror at the sun and cast its
reflection on a wall, you'll see an image of the Buddha (right).

The mirror was made in China in a process whose roots date back to the Han
dynasty (100 B.C.). Typically, the molten bronze is poured into a mold that
creates a picture in relief on the back of the mirror. The same image
appears on the wall. Seeing the result must have seemed like magic hundreds
of years ago. The Chinese called this a "light-penetrating mirror," because
they believed light had to go through the surface to reflect off the back
of the mirror!

Mirrors similar to these but made in Japan were first seen in the West in
1832. It took a full century, but Sir William Bragg, a British
crystallographer, finally published the accepted scientific explanation in
The Universe of Light in 1933. The pattern in relief on the backside
provides the key to the reflected image by creating areas on the disc where
the thickness of the bronze varies, Bragg said. When the
mirror-makerscratches and scrapes the surface to smooth it, "the thinner
parts of the mirror bend and give to the tool more than the thicker parts
which lie over the prominences of the pattern. When the pressure has
passed, the thin parts recover and rise slightly above the average level of
the face," becoming more convex than the thicker portions. The
imperceptible irregularities on the front cause the image in the
reflection.

The same explanation was accepted by Joseph Needham, author of Science and
Civilization in China (1962); by Robert K. G. Temple in China: Land of
Discovery (1986); and most recently by Derek Swinson, a physicist at the
University of New Mexico, writing in the May 1992 issue of The Physics
Teacher.

The problem is that my magic mirror doesn't work that way. The design on
the back is a circle of Chinese zodiac symbols, not a Buddha. The back-side
has nothing whatever to do with the image cast on the wall.

Ron Edge of the University of South Carolina's department of physics and
astronomy examined a mirror like this one and agrees that accepted
explanations are "definitely wrong." He and a student, Tom Brouckson,
directed a fine beam of light at it and determined that the face was
covered with very slight ridges (rather than indentations), each with a
slope of only 0.1 degree to the rest of the surface, so they' reinvisible
to the naked eye. Each line of the reflected image is dark, sandwiched
between two bright lines, as we would expect from a ridge. The disc's
slight convexity is important because it magnifies the reflected image and
makes even minor irregularities visible.

James Dalgety of Britain, who obtains these mirrors from China, has
theorized that the zodiac signs were added to the backs, over the Buddha
design. to mislead people and to keep secret what the reflection will be.
Edge thinks the Buddha ridges were cast on the face of the mirror and then
polished down until they just vanish. I tend to believe that either these
mirrors are made a whole new way or perhaps that Western science, from
Bragg onward, has been fooled by a deliberate trick played by the ancient
bronzeworkers--who made the backs match the images cast only to give the
false impression that the one caused the other. (I'll expand on this next
month after presenting another Chinese bronze mystery, the "spouting
washbasin.")

Dalgety will sell these mirrors for $75, postpaid, and will accept checks
in U.S. dollars from U.S. banks. Write: Enigma Designs, James Dalgety,
Manmead, N. Barrow, Yeovil, Somerset, United Kingdom BA22 7LZ. ff he
receives a lot of orders, he'll have to obtain more mirrors from China, and
it could take two or three months to fulfill all orders.

PHOTOS: On the back of the Magic Mirror (left) is a raised design. On the
front is a disc of polished bronze that seems to be an ordinary
mirror--until you reflect sunlight off of it. Then, the Buddha appears
(above).