180 DETAILED REPORT ON ALABAMA CLAYS. 



ware clay from Harrisonville, Cass Co., Mo.,* but the lat- 

 ter having nearly 3 per cent, more fluxes fuses at a lower 

 temperature. 



(No. 65a. S.) 

 POTTERY CLAY. 



TEN MILES SOUTHEAST OF HAMILTON, MARION CO. 



A moderately gritly, medium grained clay with a few 

 mica scales, it required 28.9 per cent, of water to make a 

 workable mass, which is rather lean. The air shrinkage 

 of bricklets made from this was 6.5 per cent, with &n 

 additional shrinkage of 5.5 per cent, in burning, making 

 a total shrinkage 12 per cent. 



The average ten-ile strength of air dried briquettes 

 was 58 Ibs. per sq. inch with a maximum of 6.5 Ibs. per 

 square inch. 



Incipient fusion occurs at 1950 F., vitrification at 2150 

 F., and viscosity at 2350 F. 



It burns to a grayish buff color. 



The chemical composition is as follows: 



Analysis of Pottery Clay, 10 miles southeast of Hamilton, Marion Co. 

 (No. 65a f S. 



Silica (total). ............................... 70 . 00 



Alumina ................................... 21.31 



Water ..................................... 6.35 



Ferric oxide ................................ 2.88 



Lime ....................................... 20 



Magnesia ................................... tr. 



Alkalies .................................... tr. 



Moisture ................................... .50 



i 101.24 



Free silica ( sand) 45 80 



Total fluxes 3.08 



Specific gravity 2.10 



*Mo. Ge-)l. Survey XI, p. 315. 



