FIRE CLAYS. 147 



4MQ,lvaia of Bauaite, Book Run, Oherokee Oo., No. 6. 



Silica 9.50 



Alumina , 61.14 



Ferric oxide trace 



Lime trace 



Magnesia trace 



Water 31.20 



101.84 



The foregoing tests of these bauxites show a high 

 refractoriness, but also a very high shrinkage which 

 increases apparently with the fineness of grain. It 

 is difficult to draw conclusions from six specimens, 

 however, just what the relations of silica, alumina, 

 water and. size of qfrain are which influence the shrink- 

 age. 



All of these bauxities would, of course, have to be 

 first calcined if used for refractory purposes; but 

 they could then be mixed with a small amount of 

 plastic clay to serve as binder and would then make 

 a very refractory article. In my report I shall dis- 

 cuss this point. 



(No. 117) 

 PIKE CLAY. 



NEAR VALLEY HEAD, DEKALB COUNTY. 



The clay mines of the Montagues are situated d^bout 

 two mile up the railroad from Valley Head, and .a 

 few hundred feet to the west of the track. Several 

 grades of clay are obtained from the mines, but they 

 are not restricted in any case to certain layers. The 

 following sample tested is what is known at the mines 

 as the first grade, and its refractory character is not 

 by any means low. 



The material is a white sandy clay, rather coarse 



