180 DETAILED REPORT ON ALABAMA CLAYS. 



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

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

 temperature. 



(No. 65a. S.) 

 POTTERY CLAY. 



TEN MILES SOUTHEAST OP 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 an 

 additioual shrinkage of 5.5 per cent, in burning, making 

 a total shrinkage 12 per cent. 



The average tenaile strength of air dried briquettes 

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

 square inch. 



Incipient fusion occurs at 1 950° F.,vitrification at 2150° 

 F., and viscosity at 2350° F. 



It burns to a grayish buflf color. 



The chemical composition is as follows: 



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

 (So. 6Sa. B.) 



Silica (total) 70 . 00 



Alumina 21.31 



Water 6.35 



Ferric oxide 2.88 



Lime .20 



Magnesia tr. 



Alkalies tr. 



Moisture .50 



101.24 



Free silica ( sand) 45 80 



Total fiuses 3.08 



Specific gravity 2.10 



*Mo. Qeol. Sorrey XI, p. 315. 



