CLAYS OF NEW YOKK ' TSO 



age tensile strengtli of only 11 pounds to tlie sqnare incli, -with, a 

 maximum of 14 pounds. In burning tHe total shrinkage up to cone 

 12 amounted to 18. Y^; tlie color was whitish. At cone 34 in the 

 Deville furnace the clay showed no sign of fusion whatever, and 

 is therefore highly refractory. 

 A mechanical analysis yielded: 



Clay substance . . . . ' 97.66 



Silt, very fine sand, fine sand 2.. 00 



99.66 



The composition is: 



Silica 47.40 



Alumina 39 . 01 



Ferric oxid .15 



Lime tr 



MagTiesia tr 



• Alkalis tr 



Water 14. 10 



Total 100.66 



The rational composition is: 



Clay substance 97 . 50 



Eeldspar 



Quartz 



[ 1-^° 



The sandy clay was more plastic, and required only Slfo of water 

 to mix it up. The air shrinkage was less, being only 6.5^, and the 

 tensile strength was 20 pounds a square inch. At cone 9 the total 

 shrinkage was 15^ and the color whitish. In the Deville furnace at 

 cone 34 the clay remained unaffected. 



