106 CASEIN. 



The mass may be made more impervious to water by mixing 

 with it a solution of ferrous sulphate or copper sulphate, or 

 an alkaline solution of shellac, mixing the whole well and 

 pressing it in metal moulds. The finished articles can be 

 worked in the same way as wood. 



FIREPROOF CELLULOSE SUBSTITUTE. 



A hard, glossy and fireproof substance is obtained by the 

 following recipe. A solution of 200 parts of casein in 50 

 parts of strong ammonia and 400 of water, is mixed with 



Quick-lime .... ... 240 parts. 



Aluminium acetate 150 



Alum 50 



Gypsum 1200 



followed by 100 parts of linseed oil. 



The mass is kneaded until perfectly homogeneous, and 

 is then rolled into sheets of any desired thickness. These 

 are dried and pressed in hot metal moulds, or else are re- 

 duced to powder, filled into moulds and exposed to heavy 

 pressure. The moulded articles are dipped into a bath of 

 10 parts of phosphoric acid and 100 of water, and are after- 

 wards dried, polished and varnished with a solution of 

 shellac, consisting of 3 parts of shellac, 1 of borax and 20 

 of boiling water. 



According to another recipe, plastic articles of all kinds, 

 and especially decorations and ornaments of paper, can be 

 made to appear as though made of plaster of Paris, stamped 

 sheet metal or carved wood. Two press moulds are used : 

 one positive, the other negative, and both fitting accurately 

 in one another. A few sheets of ordinary paper, previously 

 moistened, are laid in the negative mould and worked with 

 the finger-tips so as to fill up all the depressions in the 

 mould. Casein glue is applied to each sheet before the next 

 is put in ; and when a sufficient thickness has been attained 

 (14 to 15 pieces of ordinary packing paper are generally 



