178 DETAILED REPORT ON ALABAMA CLAYS. 



Analysis of Refr.ictory Pottery Clay, Shirley's Mill^ Fayette Co., (No. C>8 -SV> 



Silica (total) 72.20 



Alumina 17.42 



Water and loss 7.40 



Ferric oxide 2.40 



Lime trace 



Magnesia trace 



Alkalies 56 



Moisture.. .12 



100.10 



Free silica (sand) 52.31 



Total fluxes 2.96 



Specific gravity 2.28 



This clay might work for an inferior grade of fire brick,. 

 or also for pressed brick of a light color, or even for 

 potter's clay. It resembles rather closely in composition 

 a stoneware clay from Commerce, Scott Co., Missouri,* 

 agreeing closely in every respect except the tensile 

 strength. For sake of comparison the properties of the: 

 Commerce clay are given herewith: 



Analysis of Clay, Commerce, Mo. 



Silica '71.78 



Alumina 17.01 



Water 8.13 



Ferric oxide 2.01 



Lime 34 



Magnesia 43 



Alkalies . .78 



100.48 



Total fluxes 3.56 



Specified gravity 2.03 



Incipient fusion 2000 F. 



Vitrificaton 2200 F. 



Viscosity 2400 F. 



Average tensile strength 225 Ibs. per sq. inch 



Maximum tensile strength 254 Ibs. per sq. inch 



*Mo. Geol. Survey, XI, 350. 



