80 CLAYS AND CLAY INDUSTRY. 



Since in drying molded-clay objects the evaporation is greatest 

 from the edges and corners of the ware, the incrustations may be 

 heaviest at these points, but the more rapidly the water is evapo- 

 rated the less will be the quantity of soluble salts deposited on 

 the surface. Incrustations which appear during drying are found 

 more commonly on bricks made from very plastic clays, which, 

 owing to their density, do not allow the water to evaporate 

 quickly. 



