32 SEMIVITRIFICATION. [II. 



Porcelain clay from Halle, washed over and 



dried . ;■ 31 



Dry quartz sand 43 



Gypsum 14 



Porcelain cullet 12 



It is to be mixed thoroughly with 300 pts. of water, and 

 then incorporated successively with aqueous solutions of 



Bichromate of potassa 19 



Protosulphate of iron 100 



Acetate of lead 47 



Ammonia is now added until the complete separation of the 

 iron, and the potassa and ammonia salts then removed by 

 washing and decantation. 



Red Pigmeyits for Porcelain. — Salvetat, in his elaborate and 

 valuable paper (Ann. de Chem. et de Phys. 1849) upon the 

 red pigments used in porcelain painting, gives analyses of 

 the celebrated chromatic series known as Pannetier's. The 

 shades which they impart are said to be unequalled for beauty, 

 brilliancy, and transparency. 



The series consists of eleven tints, as follows : 

 Orange. 



No. 1, or Capucin red. 

 No. 2, or blood " 

 No. 3, or flesh " 

 No. 4, or carmine " 

 No. 5, or lake " 



No. 6, or pale violet red. 

 No. 7, or iron " " 

 No. 8, or dark " " 

 No. 9, or very dark violet red. 

 Gray. 

 The flux is the same for all, and consists of silex, borax, and 

 minium. The coloring matter of all but the orange and Nos. 

 8, 9, 10, is exclusively peroxide of iron ; and the modifica- 

 tions of tint are due to a variation of the proportions, and 

 particularly to a difl"erence in the intensity of heat employed. 



