A PRELIMINARY REPORT ON CLAYS OV VLORIDA 163


 MEDIUM BRICK.
 Weight Dimen- Area, square Load Unit load, pounds
 pounds. sions. inches. pounds. per square inch
No. 1-4.3 3.7x7.6 28.12 73,560 2,617
No. 2-4.3 3.6x7.7 27.72 73,190 2,640
No. 3-4.2 3.6x7.6 27.36 75,140 2,746

 A verage ...................................................... 2,668
 SOFT BRICK.
 Weight Dimen- Area, square Load Unit load, pounds
 pounds. sions. inches. pounds. per square inch
No. 1-4.1 3.7x7.8 28.84 106,200 plus 3,680 plus
No. 2--4.0 3.7x7.7 28.49 99,890 3,506
No. 3-4.0 3.6x7.6 27.36 106,200 plus 3,882 plus

 A verage ...................................................... 3,689 plus
 The Ocklocknee clay has the following physical properties:
 Physical Properties of the Ocklocknee Clay (Lab. No. 0-30).
 Plasticity, judged by feel............ Excellent.
 W ater of plasticity................. 26.00%
 Pore water ........................ 0.52%
 Shrinkage water ................... 25.48%
 Linear air shrinkage................ 12.2 %
 Volume air shrinkage............... 33.2 %
 Modulus of rupture, average........ 988.0 pounds per square inch.
 Slaking test ....................... 2 days.
 Steel hard at cone 010.
 Fire tests:
Temperature. Linear Shr. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent.
 950'C. 0.2 13.10 28.40 Reddish brown.
 1050 0.7 14.22 29.00 Reddish brown.
 1150 0.8 10.50 25.50 Reddish brown.
 1190 0.3 9.75 24.00 Reddish brown.
 1230 0.3 9.60 23.20 Reddish brown.
 1310 3.8 9.05 22.75 Reddish brown.
 1370 4.3 9.55 20.30 Reddish brown.
 1430 4.8 8.42 18.75 Reddish brown.









 7~A.



 FIG.. 23-General View, Ocklocknee Brick Co., Lawrence, Gadsden County.