POTTERY OR STONEWARE CLAYS. 175 



V 



This clay would probably woik very well for stone- 

 ware. 



(No. 71 S.) 

 POTTERY CLAY. 



W. DOTY, FAYETTE CO. 



A fine grained, red clay, with little coarse grit, and 

 very few mica scales. Slakes quickly to fine grains. It 

 required 34.3 per cent of water to work it into a mass of 

 good plasticily, the bricklets made from it shrinking 7 

 per cent, in drying and an additional 6 per cent in burn- 

 ing, giving a total shrinkage of 13 per cent. 



The tensile strength of the air dried briquettes, wa& 

 on the average; 116 pounds per square inch, with a max- 

 imum of 155 pounds. 



Incipient fusion occurs at 2000 F., vitrication at 

 2200 F., and viscosity at 2400. 



It burns to a dense hard body of a nice deep red color,, 

 which darkens as vitrification is approached. 



The composition of the clay is as follows : 



A nalysis of Pottery Clay, W. Doty, Fayette Co. ( No- 71, S. ) 



Silica (total) 65.58 



Alumina , 19.23 



Water 5.50 



Ferric oxide 4.48 



Lime tr. 



Magnesia tr. 



Moisture 1.40 



96.19 



Free silica (sand) A45.85 



Total fluxes 4.48 



Specific gravity 2.42 



