164 DETAILED REPORT ON ALABAMA CLAYS. 



2500 F. The average tensile strength of the bricklet 

 was 155 pounds per square inch, with a minimum of 

 140 pounds and a maximum of 168 pounds, which is 

 very good. 



The composition of the clay is as follows: 



Analysis of Fire. Clay, Hull's Station, Tuscaloosa Co. (No. B.) 



Silica 61.25 



Alumina 25.60 



Ferric oxide 2.10 



Lime 25 



Magnesia .82 



Alkalies 1.35 



Ignition 8.10 



Total fluxes 



(No. 118). 



FIKE CLAY, 



J. C. BEAN, TUSCALOOSA COUNTY. 



It is a fine grained clay, with very little grit, and of 

 homogeneous structure. When immersed in water it 

 slakes witih extreme slowness. The addition of 36 

 per cent, otf water to the clay gives a very plastic mass 

 and the bricklets made from this had an air shrinkage 

 of 12 per cent. 



When burned to 2200 F. the total shrinkage 

 amounted to 18 per cent., the bricklet was grayish red 

 in color, and very dense, incipient fusion having 

 occurred. When heated to cone 27 in the Deville 

 furnace it only vitrified. 



The burning dense of this clay at such a t^n pera- 

 ture. and the great difference in temperature between 

 the points of incipient sintering and vitrification are 



