

CASEIN ADHESIVES AND PUTTIES. 95 



CASEIN CEMENT FOR STONE. 



Fresh curd, pressed to expel the whey, is kneaded in 

 warm water with about one- fourth its weight of powdered 

 slaked lime, to form a soft, plastic mass which must be used 

 immediately as it hardens quickly. To give the cement 

 more body which is desirable for use with stone the lime 

 should have been mixed beforehand with about its own 

 weight of fine sand or brickdust, the mass being made up 

 to a stiff mortar with water before adding the curd. The 

 surfaces to be cemented must be well moistened. 



Another excellent cement for this purpose, that sets 

 slowly, becomes very hard and answers admirably for pro- 

 tecting joints in stonework from water, alkalies, etc., consists 

 of fine cement mixed to a stiff paste with one-fourth its own 

 weight of fine brickdust, and with moistened curd. 



A good cement for wood is made of equal quantities of 

 powdered quick-lime, dry curd and albumen, mixed together 

 by stirring. 



INSOLUBLE CASEIN. 



Morin makes an insoluble casein by treating the com- 

 mercial article, preferably in the form of powder, with 

 trioxymethylene, previously dissolved or suspended in water. 

 The mixture is then heated to about 60 C., the casein soften- 

 ing to a pasty mass which can be shaped or moulded as 

 desired. Under the influence of the small quantity of water 

 that remains in the mass after pressing, the trioxymethylene 

 is decomposed into formaldehyde, and this substance being 

 in intimate association with the casein renders) the latter in- 

 soluble. This reaction proceeds slowly, so that no bubbles 

 are formed. The mass may be incorporated with emery or 

 the like, to form grindstones, or may be coloured in any 

 desired way. 



