1879. 1 rrofrssnr Ayrion on the Magic Mirror of Japan. 35 



thicker parts of the mirror would yield less to tlio pressure of the 

 rod than the thinner, and so would be made less convex, or oven th(!y 

 might not spring back, on tlic removal of the rod, and so remain 

 actually concave. Again, since we find that scraping the face of the 

 mirror is the way in which it is made convex, and the back therefore 

 concave, we might conclude that a deep scratch on the back would 

 make the back convex and the face slightly concave. Such a con- 

 cavity, as we have proved, would explain the phenomenon of the 

 bright line appearing in the reflection of sunlight on the screen which 

 was observed by Professor Atkinson to correspond with the scratch 

 on the back. 



After the scratches produced by the mcgcho arc removed, the 

 mirror is polished with whetstones and then with charcoal. The 

 face now becomes fairly smooth, but it still generally contains some 

 few cavities ; these the maker fills up from a stock of copper balls of 

 various sizes which he has at hand. (It was probably the presence of 

 these bits of copper that ledOu-tseu-hing to believe that the explana- 

 tion of the cause of the magic mirrors was the inlaying of different 

 metals.) The face of the mirror is finally rubbed over with a mer- 

 cury amalgam containing fifty per cent, of tin, by means of a small 

 straw brush, or with the hand. 



The lecturer then referred to the various metal mixtures employed 

 by the JajDanese in making their mirrors, the best being composed of 

 75 per cent, of copper, 23 of tin, and 2 per cent, of a natural sulphide 

 of lead and antimony. 



Although the Japanese have paid no attention to the magic mirror 

 which has created such interest in Europe, they have in connection 

 wdth their priestcraft employed mirrors, on the surface of which, if 

 looked at very obliquely, could be seen the faces of saints, which 

 were not in any way connected with the pattern on the back of the 

 mirror. The accompanying figures represent the front and back of 

 one of these religious mirrors, about four and one-fifth inches high 

 and three and a half wide, and which exists at Kamakura, the old 

 caj^ital of the former Emperor of Japan, the Shogun, in a temple to 

 which great reverence is paid on account of the saj)posed supernatural 

 character of this mirror. In the polished surface, when looked at 

 very obliquely, is seen the face of a Buddhist priest, and the back is 

 ornamented with a moon rising from the sea, a rosary, and a plum 

 tree. 



The lecturer also exhibited two mirrors of this kind which he had 

 had made in consequence of the belief expressed by one of the 

 Japanese mirror makers, that the phenomenon of the so-called magic 

 mirrors was produced by chemical action on the surface. But the 

 result of the experiment had been, that if the face of a mirror which 

 had been chemically acted on was polished until every trace of the 

 marks disappeared for direct or oblique vision, then they also dis- 

 appeared in the image produced by reflecting a beam of light on to a 

 screen, and consequently that it did not seem possible, as far as his 



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