230 FLORIDA GEOLOGICAL SURVEY-15TH ANNUAL REPORT

 A sample of the washed clay from the Florida China-Clay Corporation's plant, near Okahumpka, had the following physical properties:

 Physical Properties of the Florida China Clay Corporation's Sedimentary Kaolin (Lab. No. o-83).
 Plasticity, judged by feel........... Excellent.
 W ater of plasticity................. 34.65%
 Pore water ........................ 0.59%
 Shrinkage water ................... 34.56%
 Linear air shrinkage................ 9.5 %
 Volume air shrinkage.............. 25.8 %
 Modulus of rupture, average........ 201.0 pounds per square inch.
 Slaking test ....................... 3 minutes.
 Steel hard at cone 1.
 Fire tests:
 Temperature. Linear Shr. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent.
 950*C. 4.5 34.16 42.20 White.
 1050 5.5 27.08 45.75 White.
 1150 6.5 16.12 32.50 White.
 1190 12.5 6.78 16.10 White.
 1230 13.5 4.94 12.30 White.
 1310 15.5 4.86 12.60 White.
 1370 16.0 1.60 6.65 White.
 1430 17.5 1.37 4.38 Light gray.
 A sample of the washed clay from one of the mines near Okahumpka was tested in the laboratory of the Bureau of Mines1 at Columbus, Ohio. It had the following physical properties:

 General Physical Tests of Washed Clay from Okahumpka.
 W orkability ....................... Very plastic; molds well.
 W ater of plasticity................. 49.78%
 Volume air shrinkage.............. 32.15%
 Linear air shrinkage, calculated.... 12.20%
 Modulus of rupture, average........ 181.00 pounds per square inch.
 Deformation temperature, cone 31 plus.
 Steel hard at cone 3.
 Develops small cracks in firing.
 Fire tests:
Temperature. Linear Shr. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent.
 190*C. 12.1 32.10 28.30 White.
 1250 12.5 38.11 27.05 Faint cream white.
 1310 14.4 37.33 23.41 Faint cream white.
 1370 18.7 46.30 7.40 Cream.
 1410 20.3 49.40 2.20 Buff.

 'High Grade Clays of the Eastern United States, U. S. Geol. Survey Bull. No. 708, p. 291, 1922.