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17 
_ the Japanese women what the sword was to the Japanese man, 
the most precious thing she had. It had a religious signi- 
ficance, and in places where the Japanese had given offerings to 
their gods could be found many thousands of swords and mirrors. 
Those mirrors were not like ours of to-day. They were not made 
of glass but of bronze silvered in a primitive way with an amalgam 
of tin and mercury. Unfortunately when the polish wore off it 
could not now be replaced, as Western art had swept away the 
art of Japanese mirror-making. The mirrors were kept covered 
up to be brought out only when wanted. The lecturer showed 
pictures on the screen of several Japanese mirrors, calling particular 
attention to the figures on the back which were either heraldic, 
symbolic, or of letters. Throughout the writings of medieval 
times could be found casual references to magic mirrors. Pythagoras 
was said to have been able to send a word to a besieged city by 
writing it in blood on a mirror and throwing the disc of light upon _ 
the moon. He believed that what Pythagoras did was to reflect 
the sun’s light from a mirror. A Japanese magic mirror had when 
ordinarily viewed a plain polished surface. When, however, the sun’s 
‘rays were reflected from the surface upon a screen the characters 
in relief on the back were seen in the reflected image. This Prof. 
Thompson showed by means of an arc-light in place of the sun, 
reflecting the light on to the lantern screen from the Japanese 
mirrors, of which he has made a collection. The Japanese were not 
aware of the cause of the “‘ magical” properties of their mirrors, 
the discovery having been first made by the English professors, 
Ayrton and Perry, while living in Japan. The explanation given 
by them is that under the heavy pressure used in the art of polishing 
the thin metal bends slightly, those portions which are strengthened 
- by the relief of the design on the back bending less than the spaces 
between. It results then in these interspaces being less abraised 
by the polishing tool than the backed portions, the latter, after 
removal of the pressure, forming slight concavities in the polished 
surface. That this is the true explanation has been proved in 
several independent ways. The concavities have been detected 
by measurement with a spherometer. Again, Prof. Thompson 
having had a cast made from the surface of a magic mirror, the 
cast was found to have the magic properties of the original. _ 
Exhibits were kindly lent by Mrs. Beach, Mr. Hugh Findon, 
Mr. L. B. Hall, Mr. Montague F. Hopson, Rev. H. N. Hutchinson, 
Mrs. Park, Mr. James E. Whiting, Mr. M. Yeatman Woolf and 
Messrs. Watson and Son. A Foucault’s Pendulum was shown by 
Mr, C. O. Bartrum. A selection of music was given during the 
