Plate I. depicts a mirror in the author’s possession, about 7 inches in diameter, the back of which bears in high relief a crest in the form of a bird (_hoho_). The casting has evidently been tooled up to give greater sharpness, and the part in high relief has been ground and polished. The pattern which this mirror casts from its face is shown beside the mirror, both being photographically reproduced. This mirror shows the pattern with sunlight, or with the light of the electric arc, or with lime-light. It can also be shown to a few persons at a time by means of the flame of a paraffin lamp twenty feet away, or even by the light of an ordinary candle a couple of feet away. In the case of these weaker sources of light the mirror must be held close to the white screen or card upon which the image is to be received. Plate II. is taken from a mirror upon which there is, in high relief, polished, a crest consisting of the imperial _kiri_ within a circlet, together with a landscape of storks and bamboos in lower relief. In this case only the ornament in high relief produces any effect: and it is interesting to notice that, whereas the circlet on the back is a simple flat band, the circlet in the image (which is distorted in consequence of a general distortion of the mirror face as a whole) presents double lines. The author is disposed to think that the ornament on the back must in this instance have been subjected to polishing subsequently to the front face. Plate III. represents a very thin mirror, about 9-1/4 inches in diameter and not more than 0·04 inch thick in its thinnest parts. The central character in high relief is surrounded with the seven precious objects in lower relief. Most of these may be seen more or less distinctly in the luminous pattern cast from the front. Plate IV. is a rather smaller mirror, 6-7/8 inches in diameter, having low-relief ornament only; yet of this almost every detail is visible in the image as cast by electric light or sunlight. Plate V. shows a mirror which has two Chinese characters in high relief, polished, with a background made up of symbols of longevity--pine-tree, two storks, and a hairy-tailed tortoise. But though these are in almost as high relief as the polished letters, only the former are to be distinguished in the image. Here again the author conceives that the two letters have been polished down subsequently to the face; the pattern of these parts having been thus, to a minute degree, forced into the reflecting surface.