FIRE CLAYS. 146 



The air shrinkage was 2 per cent. 

 At 2400° P. the brick was very loose and crumbly. 

 At 2500° F. shrinkage 11 per cent. 

 At 2600° F. shrinkage 18 per cent. 

 At 3150° F. shrinkage 22 per cent. Totally unaf- 

 fected. 



Analysis of Bauxite, Rook Bun, Cheroleee Co., No. 3. 



Silica 3.30 



Alumina 69.01, 



Ferric oxide .20 



Lime 



Water 28.10 



100.66 



48. (No. 4.) Three mixtures were made up as 

 follows : 



a. 33 per cent, smaller than 20-mes'h. 

 67 per cent. 10-20 mesh. 



b. Under 30 mesh. 



c. Under 20-mesh. 



All three gave lean mixtures. 



d. Took 23 per cent, water to work it up. 



b. Took 20 per cent, water to work it up. 



c. Took 24 per cent, water to work it up. 



The air shrinkage was 6. 2 per cent, c. 1 per cent. 



At 2400° F. b showed 10 per cent, shrinkage and 

 the particles barely colored. 



At2500°F. & had shrunk 11 per cent, and held; 

 c 13 per cent, but was very loose. 



At 2600° F. b. and c. had both shrunk 13 per cent, 

 but could still be scratched by the knife. 



At 3000° F. the bauxite was unafPected, and show- 

 ed a total shrinkage of 17 per cent. 



