A PRELIMINARY report on clays oe elorida 
205 
The lower clay has the following physical properties: 
Physical Properties of the Allentown Lower Clay (Lab. No. 0 - 81 ). 
Plasticity, judged by feel... 
Water of plasticity. 
Pore water ... 
Shrinkage water .. 
Linear air shrinkage. 
Volume air shrinkage. 
Modulus of rupture, average 
Slaking test. 
Steel hard at cone 1. 
Excellent. 
24.15% 
0.65% 
23.50% 
8.0 % 
30.6 % 
244.6 pounds per square inch. 
10 minutes. 
Fire tests: 
T emperature. 
Linear Shr. 
Per Cent. 
A bsorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
950°C. 
0.0 
21.99 
38.20 
White. 
1050 
2.0 
36.20 
White. 
1150 
5.0 
15.98 
18.60 
Brown. 
1190 
7.0 
10.28 
15.50 
Brown. 
1230 
7.0 
9.60 
10.50 
Gray. 
1310 
7.0 
2.25 
6.15 
Gray. 
1370 
9.5 
2.00 
5.95 
Gray. 
1430 
8.0 
1.52 
4.75 
Gray. 
A sample of clay taken from Blackwater Creek, two and one-half 
miles northeast of Milton, was tested by the Bureau of Standards in 
1914. 1 
Its physical properties indicate that it may be used for a good grade 
of common structural materials, but not for a vitrified product. It has 
the following physical properties : 
Physical Properties of Blackwater Creek Clay (Bureau of Standards, Sample No. 3 )- 
Plasticity. . 
Excellent. 
Water of plasticity. 
28.9% 
Linear air 
Fire tests: 
shrinkage. 
6.0% 
Temperature. 
Linear Shr. Absorption. 
Porosity. 
Color. 
Per Cent. 
Per Cent. 
850°C. 
0.64 
35.30 
Salmon. 
950 
35.80 
980 
36.20 
1010 
0.21 
34.86 
1040 
33.60 
Buff. 
1070 
32.15 
1100 
31.10 
1130 
1.44 
29.55 
1160 
29.05 
1190 
28.80 
1220 
28.05 
1250 
1.17 
27.30 
1 Sellards, E. H., Report on Tests for Paving Brick, Florida Geol. Survey Press 
Bulletin No. 7, 1915. 
