1878.] The Magic Mirror of Japan. 129 



However, lie was a little astonished to find, during his residence 

 in Japan, that, although the magic mirror was supposed in Europe 

 to be a standard Japanese trick, and although it had been considered 

 by Sir Charles Wheatstone as one of the best proofs of the ingenuity 

 of the workmen of Japan, still that it formed no part of the stock-in- 

 trade of any of the numerous conjurors in this country, and was never 

 exposed for sale in any of the curiosity-shops. He was also still more 

 surprised when, during the visit of the " Challenger," Sir Wyville 

 Thomson and himself were strolling about Tokio, to find that, although 

 they asked at several mirror shops for a mirror that showed the back, 

 a specimen of which Sir Wyville much desired to possess, the shop- 

 keepers seemed not to have the slightest knowledge of what was wanted. 

 At that time the author could not but regard the total apparent ignorance 

 displayed by the Japanese mirror- vendors on this subject as the result 

 of his limited knowledge of the language, and he had then no notion 

 that, in Japan at any rate, the phenomenon was the result of no clever 

 trickery, but arose from the method in which the mirrors were pre- 

 pared. We have since learnt, however, by diligent inquiry, that, as 

 is the case with many things appertaining to Japan, so with the 

 magic mirror, the people who know least about the subject are the 

 Japanese themselves, and we think this only furnishes another proof 

 that teachers to instruct the Japanese about Japan itself are the 

 greatest desideratum. 



Our attention was next directed to the subject of the curious pro- 

 perty possessed by some Japanese mirrors by a letter from Professor 

 Atkinson, of the Tokio Dai Gaku (the Imperial University), which 

 appeared in " Nature," May 24th, 1877, and in which he says, after 

 referring to the phenomenon of the pattern on the back being ap- 

 parently reflected when sunlight is allowed to fall on the face : — 



" I have since tried several mirrors, as sold in the shops, and in 

 most cases the appearance described has been observed with more or 

 less distinctness.* 



" I have been unable to find a satisfactory explanation of this fact, 

 but on considering the mode of manufacture I was led to suppose that 

 the pressure to which the mirror was subjected during polishing, and 

 which is greatest on the parts in relief, was concerned in the pro- 

 duction of the figures. On putting this to the test by rubbing the 

 back of the mirror with a blunt-pointed instrument, and permitting 

 the rays of the sun to be reflected from the front surface, a bright line 

 appeared in the image corresponding to the position of the part 

 rubbed. This experiment is quite easy to repeat, a scratch with a 

 knife, or with, any other hard body, is sufficient. It would seem as if 

 the pressure upon the back during polishing caused some change in 



* Only a small percentage, however, of the total number of Japanese mirrors 

 that the authors of this paper have experimented on show the phenomenon clearly. 



