144 



Profs. W. E. Ayrton and John Perry. [Dec. 12 r 



Mirrors of Second Quality. 



Copper 81*3 parts. 



Tin 163 „ 



Iyo shirome 2 "4 



Mirrors of Third Quality. 



Copper 87'0 parts. 



Tin 87 „ 



Iyo shirome 4'3 



Mirrors of Fourth Quality. 



Copper 81'3 parts. 



Tori shirome 16 3 ,, 



Iyo shirome 2*4 ,, 



Mirrors of Fifth Quality. 



Copper 71 '5 parts. 



Tori shirome 28*5 ,, 



Iyo shirome is the name given to a natural sulphide of lead and an- 

 timony taken out of the impurities of the lead ore from the mines of 

 the province Iyo, in the island Shikoku. Tori shirome is a shirome 

 containing an admixture of copper. In vol. iv of the " Transactions 

 of the Asiatic Society of Japan," Dr. Greerts gives the metal-mixture 

 employed in one of the largest mirror foundries in Kioto as follows : — 



Mirrors of First Quality. 



Lead 5 parts. 



Tin 15 „ 



Copper 80 ,, 



Mirrors of Inferior Quality. 



Lead 10 parts. 



Shirome , . . 10 ,, 



Copper o . . . 80 ,, 



MM. Champion and Pellet give as the result of their analysis of the- 

 material of Chinese mirrors: — 



Copper 50*8 parts. 



Tin 16-5 „ 



Zinc 30*5 ,, 



Lead 22 „ 



One of the chief of the Tokio mirror makers tells us he never puts 

 ordinary lead into the mixture, since he finds this makes the face of 



