20 FLORIDA GEOLOGICAL SURVEY TENTH ANNUAL REPORT. 
ANALYSES OF FULLERS EARTH FROM VARIOUS LOCALITIES. 
I. 
II. 
III. 
IV. 
V. 
VI. 
Silica (Si 0 2 ) _ 
.62.83 
67.46 
58.72 
50.36 
74-90 
63.19 
Alumina (A 1 2 0 3 ) _ . 
10.35 
10.08 
16.90 
33.38 
10.25 
18.76 
Ferric Oxide (Fe 2 0 3 ) 
— - 2.45 
2.49 
4.00 
3 - 3 i 
1-75 
7-05 
Lime (CaO) __ 
2.43 
3-14 
4.06 

1.30 
0.78 
Magnesia (MgO) _ 
3-12 
4.09 
2.56 
2.30 
1.68 
Potash (K 2 0 ) _ 
Soda (Na 2 0 ) _ — __ __ 
0.74 
0.20 
:::: S 
2 . II 
.88 
1-75 ' 
1 0.21 
) 1-50 
Water (H 2 0 ) _ 
7.72 
5.6l 
8.10 
12.05 
5.80 
7-57 
Moisture 
_ _ 6.41 
6.28 
2.30 

1.70 

No. I. From Gadsden County, Florida, U. S. Geol. Sur. 17th Ann. Rept. pt. 
iii (cont.) page 880. 
No. II. From Decatur County, Georgia. Ibid. 
No. III. From Fairburn, S. D. Ibid. 
No. IV. Glacialite, Enid, Okla. G. P. Merrill, Non-metallic Minerals. U. S. 
Nat. Mus., Rept. for 1899, p. 337, 1901. 
No. V. From Sumter, S. C., U. S. Geol. Surv., Min. Reso., 1901, p. 933, 1902. 
No. VI. From Alexander, Ark. Branner, Amer. Inst. Min. Eng. Trans. XXVII, 
p. 62, 1898. Ries, Clays, p. 465, 1906. 
Physical Properties : — The most . distinctive physical property 
of fullers earth is that of clarifying oils. 
Test for Fullers Earth: — Fullers earth varies in color. That 
found in Florida is mostly light buff, brownish or yellowish, or 
olive green, gray or blue. It is not readily distinguished in gen- 
eral appearance from other clays. It is light and porous and when 
dry adheres firmly to the tongue, but some other clays are also ad- 
hesive. A practical test of fullers earth is necessary in order to 
determine its value. A test may be made by the use of a glass tube 
to 1 inch in diameter and 2 to 3 feet long. To make the test, 
support the tube in an erect position, the lower end being plugged 
with asbestos fiber. The. earth is powdered and packed into the 
tube. A mineral oil is then passed through it. If the clay is a 
fullers earth the oils will be more or less perfectly clarified, de- 
pending upon the quality of the earth. It is reported that a fullers 
earth that will clarify a mineral oil may not affect a vegetable oil, 
while an earth used to clarify a vegetable oil may be unsatisfactory 
when applied to a mineral oil. A theory of the action of fullers 
earth in clarifying oils is given by Porter as follows (U. S. Geol. 
Surv. Bull. 315, p. 282, 1907) : “Fullers earth has for its base a 
