82 CASEIN. 



forms an excellent cement. The most favourable proportions 

 for the mixture forming casein cement are 5 parts of powdered 

 casein and I part of pulverised burnt lime, mixed together 

 with sufficient hot water to make a thin paste. Casein for 

 cement may also be prepared from skim milk, by drying the 

 latter in thin layers, reducing the product to powder and mixing 

 it with 1 part of quick-lime and enough water to form a paste. 

 Blood albumen may be used in place of casein for certain pur- 

 poses, its insolubility in water after exposure to a temperature 

 of 40 C. being utilised in the paper industry. A weather- 

 proof paint may be prepared by replacing casein by finely 

 divided glue, the colours being ground with size, gelatine, 

 or gum arabic, and applied to the surface to be coated. While 

 the paint is still fresh it is gone over with a 1 per cent, solution 

 of bichromate of potash, which solidifies the coating and enables 

 it to stand washing. The same result may also be obtained 

 with a 20 per cent, solution of chrome alum, rendered slightly 

 alkaline with ammonia. 



CASEIN GLUE IN PLATES OR FLAKES. 



One hundred and fifty parts of purified dry casein are 

 mixed with 75 parts of a solution of sodium tungstate and 

 well stirred. The mass is then thickened at a moderate 

 temperature in a jacketed enamelled pan (or on the water 

 bath), i.e., is concentrated as far as possible, and is then cast 

 into moulds or poured out on a sheet of glass or marble plate. 

 If moulded it can be cut into flat slabs like glue and dried on 

 trays ; but in the other case it forms a more or less solid 

 mass (according to the percentage of water present), which 

 readily dissolves in hot water. 



BOLDER' s LIQUID CASEIN GLUE. 



H. Bolder, of Charlottenburg, prepares a glue possessing 

 the same adhesive properties as ordinary joiner's glue, but in 

 a liquid form, which is ready for use without warming and 



