128 DETAILED REPORT ON ALABAMA CLAYS. 



(No. 85.) 

 CHINA CLAY. 



CHALK BLUFF, MARION CO. 



This clay which occurs on the property of Mrs. 

 Nelson is a smooth, white, fine grained clay with a 

 conchoidal fracture. It slakes easily into angular 

 grains. It is very lean, and requires 33 per cent, of 

 water to mix it up. The tensile strength is also very 

 low, being only 15 pounds per square inch. The air 

 shrinkage is 4 er cent. 



. At 2200 Fahr. the total shrinkage was 10 per cent. 

 At. 2350, it was 15 per cent., and the bricklet incipi- 

 ently fused, with a yellowish white color. 



At 2500, the total shrinkage was 18 per cent. The 

 color was yellow. Vitrificaton occurred at 2700 F. 



In the Deville furnace, at cone 27, the clay was 

 nearly viscous. 



No analysis was made of this clay. 



4 



(No. 37 S.) 

 CHINA CLAY. 



BRIGGS FREDERICK, NEAR CHALK BLUFF, MARION CO. 



This was a fine grained clay, 90 per cent, of it pas- 

 sing through a 60 mesh sieve. The clay took 25 pel 

 cent; of water to be worked up, and even then was 

 lean and granular, fine grinding being necessary to 

 develop proper plasticity. 



The air shrinkage was 2 per cent, and the fire 

 shrinkage was the same, giving a total shrinkage of 

 5 per cent, in the case of a sample ground to pass 

 through a 30 mesh sieve. 



