cast in moulds, the surface of each half of which is quite flat save for the ornament incised on the mould for the back. The following is Ayrton and Perry’s description of the process of casting. “The material used for making the mould is a mixture of a special kind of clay (found near Tokio and Osaka), with water and straw-ash. Two suitable slabs having been formed from this plastic compound with the aid of wooden frames, a thick layer of half-liquid mixture of powdered old crucibles, or of a fine powder called _to-no-ko_, made from a soft kind of whetstone, is spread on them. The design for the back of the mirror is then cut directly on one half of the mould, or a sketch drawn on paper is first stuck on and used as a guide in cutting the design in the clay. Sometimes, but rarely, the design is stamped in the clay with a pattern wood-block cut in relief like the proposed back of the mirror. After the design is complete, a rim of the same material as that used in the construction of the mould, and having a thickness equal to that desired for the mirror, is attached to one half of the mould. The two halves are then dried in the smoke of a pine-tree fire, pressed and tied together, and laid in the casting-box at an angle of 80° to the horizon, the half of the mould on which the design has been cut being uppermost. Finally the molten speculum metal is run into a number of moulds at the same time, which, when cold, are broken up, and the castings removed. Mirrors cast in a mould, in which the design has been cut by hand, are called _ichi mai buki_, ‘mould used once,’ and are regarded as artists’ proofs, as the design on the back is well defined. To form subsequent moulds the two halves are pressed, when the clay is wet, on an _ichi mai buki_ mirror, and the pattern is in this way transferred, but the designs on the backs of the mirrors cast in such moulds are not as clear as on an _ichi mai buki_ mirror, which therefore sells for a much higher price.” Flaws in the face of the casting are filled by inserting little balls of copper--giving rise, perhaps, to the idea that inlaying was used to produce the illusions. The handle is not cast along with the disk of the mirror, but is attached afterwards. Mirror castings when they are removed from the mould are roughly flat on the face, and need to be subjected to several processes to finish their reflecting surfaces: during these processes they acquire their characteristic convexity and their high polish. The mirror is laid down on its back on a wooden board, and then scraped or scratched with a rounded iron rod about a foot long, called a _megebo_ (“distorting rod”). The process of scoring over with the blunt tool is called _mege_. After being scored all over with scratches in every direction, it is found to be convex. Next the face is scraped with a hand-scraping tool, then rubbed down with a whetstone, then polished over with a piece of magnolia-charcoal; and lastly, when quite smooth,