168 rLORIDA GEOLOGICAL SURVEY-I5TH ANNUAL REPORT


 Physical Properties of Morris and Blumer Brick Company Upper Sandy Clay (Lab. No. o-23).
 Plasticity, judged by feel............ Excellent.
 W ater of plasticity................. 24.95%
 Pore water ........................ 0.57%
 Shrinkage water ................... 24.38%
 Linear air shrinkage................ 12.7 %
 Volume air shrinkage ............... 31.1 %
 Modulus of rupture, average........ 345.4 pounds per square inch.
 Slaking test ....................... 5 m inutes.
 Overfires at cone 9.

 Fire tests:
Temperature. Linear Shr. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent.
 950"C. 0.7 11.82 23.95 Buff.
 1050 0.3 12.38 26.75 Buff.
 1150 0.3 11.68 26.45 Buff.
 1190 0.3 11.40 25.50 Buff.
 1230 0.5 11.40 26.45 Buff.
 1310 2.3 11.80 27.75 Buff.

 The lower light-colored clay has the following physical properties:
 Physical Properties of Morris and Blumer Brick Company Lower White Clay (Lab. No. 0-24).
 Plasticity, judged by feel............ Excellent.
 W ater of plasticity................. 36.40%
 Pore water ........................ 0.88%
 Shrinkage water ................... 35.52%
 Linear air shrinkage................ 8.90%
 Volume air shrinkage............... 22.05%
 Modulus of rupture, average........ 114.0 pounds per square inch.
 Slaking test ....................... 3 minutes.
 Steel hard at cone 010.

 Fire tests:
Temperature. -LinearShr. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent.
 950*C. 11.4 4.58 12.15 Salmon.
 1050 13.6 4.50 10.45 Gray.
 1150 13.6 Gray.
 1190 13.1 3.53 8.95 Gray.
 1290 13.1 2.58 6.65 Gray.
 1310 12.1
 1370 16.1

 A similar clay is exposed a few rods south of the Tampa Northern station. It may likewise be used for a common brick, but it also requires very careful drying and burning to avoid excessive cracking. Its physical properties are: