192 DETAILED REPORT ON ALABAMA CLAT8. 



appearaoce of vitrification ,while the maximum shrinkage 

 amounted to 21 per cent. Viscosity was obtained in the 

 Deville furnace at cone 27. 



This clay therefore shows an appreciable and safe dis- 

 tance between vitrification and viscosity. The tensile 

 strength is however low, averaging 75 pounds per square 

 inch, with a maximum of 97 pounds per square inch, 

 and a minimum of 68 pounds. Specific gravity, 2.41. 



(No. 26 A. Stevens.) 

 BRICK CLAY. 



WOOKSTOCK, BIBB CO. 



This is quite a plastic clay, which requires 29 per 

 cent, of water to produce its maximum plasticity. The 

 air shrinkage was 6 per cent., and the average tensile 

 strength was 101 pounds per square inch, with the max - 

 mum of 104 pounds. The fire test gave the following 

 results : 



At 2250° F., the shrinkage 10 per cent, clay incipiently 

 fused, color bufi". 



At 2400° F., shrinkage 11 per cent., color a dark buflF. 



At 2500° F., clay vitrified, color reddish. 



Viscosity occurs at cone 27 in the Deville furnace. 



The composition of the clay is : 



Analysis of BHoTe Olay, WoodstooJe, Bibi Co. (No. lU A. Stevens.) 



Silica 74.20 



Alumina 17.25 



Ferric oxide 1.22 



Lime 30 



Magnesia .40 



Alkalies tr. 



Ignition 7.35 



100.72 

 Total fluxes 1.92 



