HA RD IVICKE' S SCIENCE- G OSSIP. 



13 



The Chinese, at a very early age, knew of magic 

 mirrors, and Chin-Kouo, a Chinese writer of the 

 eleventh century, speaks admiringly of them. 



They were introduced from China and Japan into 

 Calcutta, and interested the inhabitants much ; 



POIHT 



that the witches of the Middle Ages had mirrors of 

 Eastern manufacture, with imps and secret signs on 

 the back. Probably also Chinese priestcraft, Greek 

 and Etruscan oracles, made use of them. In the 

 temple Kenchoji, situated in the ancient capital of 

 the Shogun, there is a wonderful 

 old mirror, which if looked at a 

 little obliquely reveals the face 

 of a Buddhist god. Various 

 faces of saints have thus been 

 depicted in mirrors, but this is 

 done by altogether another pro- 

 cess than that of the magic 

 mirror at present under dis- 

 cussion. 



The mirror is circular in form, 

 and is generally from three to 

 twelve inches in diameter. The 

 metal of which it is usually made 

 is a composition of copper and 

 tin, something like the specula 

 of reflecting telescopes. 



Round it is a rim of about 



to \ of an inch in breadth ; 



Fig. 7.— Converging beams of Light. 





Fig. 8. 



philosophers conjecturing how their magic property 

 (which is only possessed by a few of those which 

 come from the east) could arise. 



From their great antiquity it has been suggested 



mercury amalgam. 



this rim is thicker than the 

 inner part of the mirror which 

 contains the figures or designs. 

 The reflecting surface is more 

 or less convex and polished with 

 On the back are raised designs, 



birds, flowers, dragons, geometrical patterns or 

 Japanese scenes and myths. Occasionally mottoes 

 or Chinese characters expressive of good wishes, 

 long life, happiness, hope, are seen. The accom- 

 panying sketch gives some idea of the back of a 

 Japanese mirror. 



The handle is made of the same metal as the rest 

 of the mirror, but usually covered with bamboo. 

 Its magic property consists in this ; when the rays 

 of the sun are reflected from its polished face, on the 

 wall or screen, the figures and the design on the 

 back of the mirror are distinctly seen in bright lines 

 on a dark ground, though the back of the mirror is 

 quite hidden from the light. Various explanations 

 of this magic power have been given : 



(1) The Chinese designated them " mirrors that 

 let the light pass through them." 



(2) Ou-tseu-ling (1260-1341) explains their magic 

 property to arise from the employment of two kinds 

 of copper of unequal density, the brighter reflexions 

 being produced by the purer copper. 



(3) Sir Charles Wheatstone and Sir David 

 Brewster, both thought that the magic power was 

 produced by some clever trick on the part of the 

 maker, who drew on the face exactly similar figures 

 as those on the back and carefully concealed them 

 by polish, so that in an ordinary light they were not 

 visible. 



(4) Messrs. Arago and Biot accounted for it by 



