BRICK YARDS 235 



vapors of salt at a high heat these change to a chloride of lime, 

 leaving the soda as a sulphate, which will either not displace the 

 silica through combination or will not do it at a temperature 

 which the ware will stand without losing shape, and therefore 

 no glaze is produced. 



"Stoneware should exhibit on fracture a blue uniform tint of 

 a somewhat vitrified appearance. This varies very often, how- 

 ever, with the clay." 



Terra Cotta 



There are four companies in ISTew York who are engaged in 

 the manufacture of this product, viz.: the Celadon Terra Cotta 

 Co., the Corning Brick Co., the ISTew York Anderson Brick Co., 

 the Glens Falls Terra Cotta Co., and the IsTew York Architectural 

 Terra Cotta Co. The first-mentioned company is gradually 

 giving up the manufacture of terra cotta and turning its entire 

 attention to roofing-tile. 



The Corning Brick Co. makes its terra cotta from a Hamilton 

 shale. The New York Anderson Brick Co. makes its ware from 

 the Cretaceous stoneware clays of Staten Island ; among the 

 largest Terra Cotta works in the state are those of the Glens 

 Falls Terra Cotta Co.; the clay used by them is a portion of the 

 Hudson estuary deposit, it being of a bluish gray color with the 

 upper portions weathered to red. We give herewith a partial 

 analysis of their two clays. 



Bluish-gray. Red. 



48.35 Silica 57.46 



11.33 Alumina 21.15 



4.02 Uxide of Iron 5.52 



15.38 Lime 3.fi5 



3.17 Magnesia 1.50 



1.18 Organic Matter 



6.05 Alkalies ^ 4.72 



89.48 94.00 



The high percentage of lime in the bluish-gray clay enables 

 them, by the use of it alone, to produce a light-colored ware, 



