1870. J on the Mirror of Japun and Its Mayic QnaUtij. 27 



the cottage, the lecturer went on to say that to the majority of those 

 l)resent the investigation of tlic so-called magic properties of the 

 Japanese mirror would probably prove of yet more interest. 



This magic property, which is possessed by a few rare specimens 

 coming from the East, is as follows : — If the polished surface is looked 

 at directly it acts like tliat of an ordinary mirror, reflecting the objects 

 in front of it, but giving, of course, no indication whatever of the 

 raised patterns on the back ; if, however, a bright light be reflected 

 by the smooth face of the mirror on to a screen, there is seen on this 

 screen an image, formed of bright lines on a dark ground, more or 

 less perfectly representing the pattern on the back of the mirror, 

 which is altogether hidden from the light. 



When this appearance is seen for the first time it is perfectly 

 startling, even to an educated mind; and if the source of light is 

 sufficiently bright, as for instance a tropical sun, it is difficult for the 

 observer to divest himself of the idea that the screen is not perforated 

 with cuts corresponding with the pattern on the back of the mirror, 

 and illuminated from behind. 



This strange phenomenon was known to Sir David Brewster and 

 to Sir Charles Wheatstone, both of whom were of opinion that it 

 M'as produced by trickery on the part of the maker. Sir David 

 Brewster, for example, says in the ' Philosophical Magazine ' for 

 December, 1832: — "Like all other conjurors, the artist has contrived 

 to make the observer deceive himself. The stamped figures on the 

 back (of the mirror) are used for this purpose. The spectrum in the 

 luminous area is not an image of the figures on the back. The figures 

 are a copy of the j)icture which the artist has drawn on the face of the 

 mirror^ and so concealed by polishing that it is invisible in ordinary 

 lights, and can be brought out only in the sun's rays." 



Professor Ayrton then related how he had been quite unable to find 

 for sale in any of the shops of Japan one of these magic mirrors which 

 was suj^posed in Europe to be a standard Japanese trick, and he 

 explained how he had at length ascertained that with regard to this 

 so-called magic mirror the Japanese were the people who know least 

 about the subject. 



But these magic mirrors were known to the Chinese from the earliest 

 times, and one of their writers spoke about them in the ninth century 

 of the Christian era. They call them Theou-lwuang-kieii, which means 

 literally " mirrors that let the light pass through them," the name, of 

 course, arising from a popular error on the subject. The Roman 

 writer Aulus Gellius, who lived seventeen centuries ago, referred to 

 mirrors that sometimes reflected their backs and sometimes did not. 

 From the great antiquity of these Chinese magic mirrors the German 

 writer Herr Sterne has concluded that it is probable that the mirrors 

 with secret signs and figures of imps on the back, which formed a 

 portion of the stock-in-trade of the witches of the middle ages, were 

 of Eastern manufacture. The Italian historian Muratori gives an 

 account of the magic mirror found under the pillow of the Bishop of 



