136 DETAILED REPORT ON ALABAMA CLAYS. 



Analysis of flre clay, Peaceiurg. Calhoun Co. (No. 191.) 



Silica 51-90 



Alumina 35.00 



Ferric oxide -99 



Lime 23 



Magnesia -10 



Alkalies 55 



Ignition 11.30 



99.87 



Total Ouies 1.87 



The low plasticity of this clay would probably inter- 

 fere with its being used alone, but owing to its re- 

 fractory nature and the light color developed in burn- 

 ing it could no doubt find use as an ingredient of 

 other clay mixtures. 



(No. 127 of Mr. Stevens.) 



FIEE CLAY. 



FROM OXANNA^ CALHOUN COUNTY. 



This is a coarse and sandy clay, which mixes up to 

 a lean mass with only 16 per cent, of water. The 

 tensile strength is very low, being on the average of 

 9 to 10 pounds per square inch, and the air shrinkage 

 is 2 per cent. 



The following is the behavior of the clay at suc- 

 cessively higher temperatures. 



At 2200° F. the color was grey white. 



At 2250° F. shrinkage 3 per cent., color buff. 



At 2300" F. shrinkage and color same. 



At 2400° F. shrinkage 3 per cent., color buff, show- 

 ing specks of ferric oxide. 



At 2500° F. the shrinkage was only 2 per cent., hav- 

 ing undergone a slight swelling owing to tlie very 

 high quartz percentage. Incipient fusion had not 



