COPPER AND ZINC AS ANTAGONISTIC TO " ALKALI " SALTS 163 
Series V 
ZnCU versus NaCl — Adobe Soil 
NaCl .4 percent constant — ZnCU varying 
Table VIII shows the arrangement of the cultures in this series 
and gives the concentrations of salts used. Despite poor agreement 
between the yields of duplicate pots, it is clearly shown in the table 
that ZnCU exercises a powerful antagonistic effect to the toxic proper- 
Table VIII 
Antagonism Between ZnCh o.nd NaCl For Barley — Adobe Soil, One Crop 
No. 
i NaCl 
ZnCl2 in 
Parts per 
Wt. of Straw 
Wt. of 
Wt. Dry Mat- 
ter Above 
Wt. of 
Wt. of Total 
Added 
Million 
Grain 
Surface 
Roots 
Dry Matter 
I 
.4% 
.4% 
50 
g- 
4-50 
g- 
2.30 
g- 
6.80 
g- 
.40 
g- 
7.20 
2 
50 
7.30 
3-70 
11.00 
.60 
11.60 
3 
.4% 
.4% 
100 
6.70 
2.90 
9.60 
1.20 
10.80 
4 
100 
6.82 
2.18 
9.00 
•75 
9.75 
5 
.4% 
.4% 
300 
9.20 
4.80 
14.00 
.75 
14-75 
6 
300 
7.92 
4.48 
12.40 
.80 
13.20 
7 
.4% 
500 
6.70 
3.70 
10.40 
1. 00 
11.40 
8 
.4% 
.4% 
500 
7.16 
2.34 
9.50 
.96 
10.46 
9 
700 
6.24 
3-16 
9.40 
1-34 
10.74 
10 
.4% 
.4% 
700 
5.75 
2.75 
8.50 
.46 
8.96 
II 
5.00 
1.90 
6.90 
.40 
7^30 
12 
.4% 
.4% 
4.70 
2.30 
7.00 
.55 
7.55 
13 
5-75 
.75 
6.50 
•45 
6.95 
14 
12.20 
5-30 
17.50 
2.50 
20.00 
15 
8.44 
4-56 
13.00 
3.40 
16.40 
ties of NaCl, in so far as the production of total dry matter of barley 
plants is concerned. As regards grain and root production, the antag- 
onistic effect mentioned is not so marked, but is distinct and great 
enough to satisfy the most critical of its existence and potency. The 
poor agreement between the yields of duplicate pots, which has been 
referred to above, does not permit of an exact appraisal of the relative 
efficiencies of small and large amounts of ZnCh as antagonistic agents 
to the toxic effects of .4 percent of NaCl. Moreover, 50 parts per 
million ZnCl2, the lowest concentration of that salt employed, seems 
to be of high potency in the direction indicated. Nevertheless, con- 
centrations of 300 parts per million ZnCl2 seem to be considerably more 
efficacious than either smaller or larger concentrations of that salt. 
Only one crop was grown in the pots of this series. 
