Jan. 20,1923 
Probable Cause of Poisonous Greensand 
227 
EFFECT OF LIME ON ACTION OF TOXIC GREENSAND 
In order to test also the effect of the toxic greensand upon the growth 
of plants when used in connection with an acid or an alkaline medium, 
the solutions described below were prepared. 
A 3,000-gm. portion of Courtland greensand was extracted for 72 
hours by percolation with 3,000 cc. of distilled water saturated with 
carbon dioxid. The percolate was evaporated to dryness, heated to a 
dull red heat, dissoved with very dilute hydrochloric acid, and made up 
to a volume of 500 cc. Of this solution 50 cc. were then made up to a 
volume of 250 cc. with distilled water. In this solution com seedlings 
were grown in the manner already described. 
Another 3,000-gm. portion of the same variety of greensand was 
extracted for 72 hours by percolation with 3,000 cc. of lime water. The 
filtrate was evaporated to dryness, heated to dull red heat, and dissolved 
in dilute hydrochloric acid. The solution was neutralized with a little 
ammonia and made up to a volume of 500 cc. Of this solution 50 cc. 
were then made up to 250-cc. volume with distilled water, and com seed¬ 
lings were placed in the solution as before. 
The effect of these solutions upon the com seedlings is shown in 
Table VI. 
Table VI. —Comparative action of solutions containing salts extracted with various 
solvents 
Num¬ 
ber of 
days. 
Solution containing salts extracted with carbon dioxid. 
Sohition containing salts 
extracted with lime 
water. 
I 
Plant killed. 
Plant growing. 
2 
New plant started. 
Do. 
3 
Plant killed. 
Do. 
4 
New plant started. 
Do. 
5 
Plant killed. 
Do. 
6 
New plant started. 
Do! 
7 
Plant killed. 
Do. 
8 
Do. 
0 
Do. 
IO 
Do! 
From Table VI it will be seen that the carbon-dioxid solution was 
toxic to the seedlings, whereas the plants in the alkaline solution were 
still growing after 10 days. 
The results of analyses of the two percolates are given in Table VII. 
Table VII. —Analyses of acid and alkaline percolates 
Constituents, 
Carbon-dioxid 
extraction. 
Lime-water 
extraction. 
so,. 
Per cent. 
16. 13 
7. 20 
3. 08 
I. l6 
Trace. 
Per cent. 
5- 90 
32. 00 
CaO. 
Mn 2 0 3 ... 
. 80 
P 2 0 5 . 
Trace. 
Absent. 
Do 
7. 60 
28. 19 
Fe 3 0 3 .'. 
A1 2 0 3 . 
3. 00 
Absent. 
4. 86 
10. 86 
K 2 o. 
NaaO. 
