490 CLAYS AND CLAY INDUSTRY. 



Physical characters of clay. Herbertsville Brick Company. 



Clay and sand 

 Clay. (equal parts). 



Water required, 32.6% 15-6% 



Air shrinkage, 5-3% 3-3% 



Average tensile strength, lbs. per sq. in.,. . 108 65 



Cone 05 — 



Fire shrinkage, 0.3% 0.7% 



Color, pink red pinkish 



Condition, not steel-hard not steel-hard 



Absorption, 20.19% 14.76% 



The clay alone remains porous even when burned to- cone 5, at 

 which point its fire shrinkage was 2.7 per cent, and its absorption 

 12.98 per cent. At cone 10 the fire shrinkage was 6 per cent. 



At the other locality (No. 219), southeast of Herbertsville,. 

 on the road to West Point Pleasant, the clay is exposed in a 

 number of pits which have been dug in the woods. None of them 

 are deep, and the working face is rarely more than 4 feet high. 

 The main opening at the time the pit was visited showed a yellow,, 

 sandy clay 3 to 4 feet deep, with 4 feet of sandy overburden. In 

 this pit the clay grades horizontally into a fluffy, sandy loam, and 

 in an adjoining pit the clay is quite plastic, and contains much 

 less sand, so that the best results are obtainable by using a mix- 

 ture from several different pits. The common method consists 

 in making a mixture of the clay and loam, and for purposes of 

 comparison these tests are also given in parallel columns: 



Physical characters of clay, Isaac Tilton's brickyard, Herbertsville. 



Clay Loam Clay and loam 



Lab. No. 698 Lab. No. 699 Lab. No. 698-9' 



Water required, 29.3 % 21.3 % 25 % 



Air shrinkage, 44 % 2.5 % 4 % 



Tensile strength, lbs. per sq. in., J2> 49 7° 

 Cone 05 



Fire shrinkage, 0.2 % 0.5 % 0.3 % 



Absorption,. • 20.84% 17.64% 19.26% 



Color, light red light red light red 



Condition, not steel-hard not steel-hard not steel-hard 



Cone 1 



Fire shrinkage, 2.6 % 1.5 % 1.4 % 



Absorption, 16.93% 16.52% 16.16% 



Color, red red red 



Condition, not steel-hard not steel-hard not steel-hard 



