166 DETAILED REPORT ON ALABAMA CLAYS. 



(No. P. S.) 



POTTERY CLAY (BLUISH.) 

 FROM MCLEAN POTTERY, ELMORE co. 



A compact bluish clay which slakes rather quickly in 

 water. It shows little grit to the taste. It required 20 

 per cent, of water to make a workable mass, which to the 

 feel was smooth and plastic. This mud shrunk 6 per cent, 

 in drying and an additional 6 per cent, in burning, giv- 

 ing a total shrinkage of 1 2 per cent. The average tensile 

 strength of the air dried briquettes was 55 pounds per 

 square inch with a maximum of 66 pounds. Incipient 

 fusion occurred at 1950 F., vitrification at 2150 F. and 

 viscosity at 2400 F. 



The clay burns to a dense, smooth, bluish white body, 

 and should make a good stoneware clay. In burning it 

 had to be heated slowly. 



The analysis of it is as follows : 



Analysis of Pottery Clay, McLean's, Edgeicood, Elmore Co. (No. P. #..) 



Silica (total) 02.60 



Alumina 26.98 



Water 8.60 



Ferric oxide 72 



Lime 40 



Magnesia .36 



Alkalies .65 



Moisture .70 



101.01 



Free silica 80.10 



Total fluxes 2.13 



Sepcifiy gravity 2.37 



STONEWARE CLAY 



FROM NEAR COOSADA, ELMORE CO. 



This is a moderately fine grained but somewhat gritty 

 clay, which however is quite plastic, requiring 26.25 per 

 cent, of water to develop its plasticity. 



