838 NEW YORK STATE MUSEUM 



The composition of tlie sliale according to an analysis fiirnislied 

 by tlie Celadon terra cotta co., of Alfred center, is : 



. Silica 53.20 



Alumina 23 . 25 



Eerric oxid 10 , 90 



Lime '. . 1.01 



Magnesia 62 



Alkalis , 2 . 69 



Sulfuric acid 41 



Titanic acid 91 



Water 6.39 



Manganese oxid 52 



99.90' 

 Total fluxing impurities 15 . 74 ' 



This sliale corresponds very closely in composition to that used 

 at Kansas City, Mo./ for the manufacture of paving brick, but 

 there is a considerable difference in the fusibility, the Missouri shale 

 being very fine and consequently more fusible. 



When this factory was first started, both terra cotta and roofing 

 tile were produced, but now the Celadon terra cotta co. confines 

 itself entirely to the manufacture of vitrified roofing tile, which is 

 of a superior quality, and bears an excellent and widespread reputa- 

 tion. At first a mixture of clay and shale was used, but now the 

 latter material alone is found sufficient; the shale after grinding and 

 careful lempering is molded either by hand or steam power ma- 

 chines, and set aside to dry slowly. The tile are no longer burned 

 in saggers as was formerly done, but are placed in pockets in the 

 kiln. The shale bums to a tough, cherry red body. 



Alfred Station. A bed of shale is worked in a spur of the hill 

 on the opposite side of the valley from the station. It is similar to 



' Mo. geol. sur. 11, 565. 



