70 
FLORIDA STATE HORTICULTURAL SOCIETY. 
(3) Per cent, of the water retained by 
soil. 
■ (4) Per cent, sulphate of ammonia re¬ 
tained by soil. 
(5) Per cent, sulphate of ammonia 
retained by the soil after pouring through 
an additional 100 cubic centimeters of 
distilled water. 
The results were as follows: 
TYPE of SOIL 
1 
S. C. clay soil. 
Columbia Co. 
soil. 
East Coast typi-j 
cal pineapple soi( 
Muck soil. 
Time required to 
begin dropping. 
2 hrs. 
17 min. 
8 min. 
li min. 
No part of the first .100 cubic 
centimeters of solution pass¬ 
ed through the muck soil. 
Time of 
Completion. 
4 hrs. 
30 min. 
23 min. 
6i min. 
Per cent, of the 
water retained by 
soil. 
55 
52 
30 
Per cent, of sul¬ 
phate of ammonia 
retained. 
I 
75.9 
58 i 
34.5 
Per cent, of sul¬ 
phate of ammonia 
retain’d aft’r pass¬ 
ing through an 
additional 100 cu. 
centijmeters of 
distilled water. 
17.8 
6.6 
5-77 
90.9 
This emphasizes very forcibly the fact 
that the coarser the soil, the more rapidly 
the water and plant food get away, and 
it perhaps gives us a clearer idea of the 
conditions which exist in the pineapple 
belt. There we have a very coarse soil, 
composed of almost pure sand, through 
which water runs almost as it would run 
through a pile of stones, carrying much 
of the soluble plant food with it. The 
question then arises, what is there about 
clay soils, and other fine soils, to hold 
plant food and moisture, that is wanting 
in the pineapple soils? 
THE WORK OF OTHER INVESTIGATORS. 
The researches of Way and other emi¬ 
nent investigators have shown that most 
soils have an absorptive power with re¬ 
ference to plant food. 
In the case of phosphoric acid this is 
not difficult to explain, as the acid forms 
insoluble compounds with the iron, lime, 
and magnesium, which are present in 
most soils, and is in turn rendered slowly 
available by the action of the solutions 
contained in the roots of the plants. 
As to the absorption of the alkalies,the 
explanation is more difficult, since nearly 
all their compounds are readily soluble in 
water; the potash salts for example. Since 
most soils consist of sand, clay, and or¬ 
ganic^ matter, Way went to work to de¬ 
termine which of these constituents ex¬ 
ercised the absorptive power. Without 
describing in detail his methods it will 
suffice to say that he showed that clay 
alone is capable of absorption phenomena. 
(It should be borne in mind that the 
term absorptive power as used here re¬ 
fers to a chemical change, and not to phy¬ 
sical absorption as when a sponge absorbs 
water). 
Having shown that clay was the main 
constituent in a soil which caused the 
absorption of alkalies. Way next tried to 
trace out the particular compound which 
caused the absorption, and finally suc¬ 
ceeded in producing a hydrated silicate of 
aluminum and soda which exhibted dis¬ 
placement and absorptive properties very 
similar to those shown by the soil. 
Then Eichorn hit upon the idea of try¬ 
ing natural hydrated silicates, or zeolites 
