158 DETAILED REPORT ON ALABAMA OLAY8. 



occurs at cone 27, vitrification at cone 32 and viscos- 

 ity at cone 34. 



The tensile strength is very low, ranging from 5 

 to 10 pounds. 



The very refractory character of this clay is evi- 

 dent, but its leanness would no doubt necessitate its 

 being mixed with a more plastic clay before it could 

 be used. 



(No. 57 S.) 

 PIEE OLAY, 



J. W. WILLIAMS, PEGRAM, COLBERT COUNTY. 



A black gritty clay, which slakes easily, considera- 

 ble organic mattter present, but no pyrite or mica no- 

 ticeable. 



It required 28.6 per cent, of waiter to make a 

 workable mass, which, to the feel, was lean and 

 gritty. Bricklets made of this shrank 10 per cent, in 

 drying and 3 per cent, in burning, giving a total 

 shrinkage of 13 per cent. 



The average tensile strength of the air-dried 

 briquettes was 46 pounds per square inch. 



Incipient fusion occurs at 2150° F., vitrification at 

 2350° F., and viscosity at 2500° F. 



The clay burns to a white body, slightly tinged 

 with yellow. 



The following is its chemical composition : 



Analysis of Fire Clay, J. W. Williams, Pegram, Colbert Co. (No. 57, S.) 



Moisture 1.70 



Silica (total) 80.55, free sand 70.10 



Alumina 10.50 . 



Ferric oxide 1.53 



Lime .34 



Magnesia traces 



Water and organic matter 5.85 



100.47 

 Total fluxes 1.87 



