226 
Journal of Agricultural Research 
Vol. XXIII, No. 3 
to make 250 cc. Paraffined corks, through which a small hole had been 
bored, were placed in the necks of the flasks. Corn seedlings were 
placed on the corks so that the roots passing through the holes were well 
covered with the liquid. At the end of 24 hours the seedlings in all the 
cultures were dead. The experiment was repeated three times with the 
same result, showing that the glauconite from each of these deposits was 
toxic. 
In order to test the effect of the manganese, iron, and aluminum upon 
the growth of plants a series of experiments was conducted with corn 
seedlings in the following manner: A solution was made by extracting 
3,000 gm. of the Courtland greensand by percolation for 72 hours with 
3,000 cc. of 1 per cent hydrochloric acid. The percolate was evaporated 
to dryness and heated to dull red heat. The residue was dissolved in 
dilute hydrochloric acid and made up to 500 cc. 
From 50 cc. of this solution manganese, iron, and aluminum were 
separated. The manganese was then separated from the iron and alum¬ 
inum and added to the original filtrate. Similar solutions were prepared 
with iron and aluminum. The filtrate was then evaporated to dryness 
and the residue heated to dull red heat and dissolved in acidulated dis¬ 
tilled water. The solution was made nearly neutral with a small quan¬ 
tity of ammonia and diluted to a volume of 2 50 cc. with distilled water. 
From another 50 cc. of the solution, made up to 100 cc. with distilled 
water, the manganese, iron, and aluminum were all removed by pre¬ 
cipitation with ammonia. The precipitate was discarded. The filtrate 
was evaporated to dryness and heated to a dull red heat until all the 
ammonium salts had been removed. The residue was then dissolved in 
distilled water acidulated with hydrochloric acid, neutralized with am¬ 
monia, and made up to 250 cc. with distilled water. 
The effect of these solutions upon the growth of com seedlings was 
tested in cultures in the manner described above. The results are 
given in Table V. 
Table V .—Comparative action on corn seedlings of various solutions prepared from 
Courtland greensand 
Num¬ 
ber of 
days. 
Manganese in solution 
(iron and aluminum 
removed). 
Iron in solution (man¬ 
ganese and aluminum 
removed). 
Aluminum in solution 
(iron and manganese 
removed.) 
Soluble salts in 
solution (iron, man* 
ganese, and alumi* 
num removed.) 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Plant killed. 
Plant killed. 
Plant killed. 
Plant growing. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
New plant started. 
Plant killed. 
New plant started. 
Plant killed. 
New plant started. 
Plant killed. 
New plant started. 
Plant killed. 
New plant started. 
Plant killed. 
New plant started. 
Plant killed. 
New plant started. 
Plant killed. 
New plant started. 
Plant-killed.. 
New plant started. 
Plant killed. 
From Table V it will be observed that none of the seedlings survived 
in the solutions containing either the manganese, iron, or aluminum, 
while in the solution from which these had been removed they were 
still growing after 10 days. 
