162 DETAILED REPORT ON ALABAMA CLAYS. 



Analysis of Stoneware Clay, Blount Co. (No. 204). 



Silica 61.50 



Alumina 26.20 



Ferric oxide 2.10 



Lime 0.50 



Magnesia 0.43 



Alkalies 0.70 



Ignition 7.29 



98.72 

 Total fluxes 3.73 



While this clay is not highly refractory, at the same 

 time it has about the right refractoriness to be used in the 

 manufacture of stoneware, and owing to the dense body 

 to which it burns, is exeellently adapted probably to mix 

 with more opened grained clays, which require a good 

 binding material. 



(No. 192.) 



POTTERY CLAY 

 FROM C. C, DAVENPORT, ROCK RUN, CHEROKEE CO. 



A green clay, of extreme fineness of grain, great density 

 and breaking with a conschiodal fracture. In water it 

 slackens rapidly to a flocculent mass. 



It took 30 per cent of water to work it up and it yielded 

 a lean and somewhat granular mass, which had an air 

 skrinkage of 9 per cent. 



The bricklets made from this clay burn to a greenish 

 brown color, and vitrify easily at about 2000 F. 



At about 1800 F. incipient fusion occurs, with total 

 shrinkage of 18 per cent., and color brown. The clay 

 fuses to a glassy mass at about 2150 F. 



The average tensile strength of the air dried briquettes 

 was 62 pounds per square inch, with a maximum of 70 

 pounds. 



The analysis of the clay shows as follows : 



