COPPER AND ZINC AS ANTAGONISTIC TO " ALKALI " SALTS I67 
j 
i 
1 m^M 
M 
^roNaCL ^%NaCL ^%MaCi f?%NQCL 
200CuS0^ 300CuSO, mCuSO, iOOCuSO, 
Fig. 2. CUSO4 vs. NaCl. Showing yields of grain from Oakley soil, first crop 
with and without different salt treatment. The duplicate vials represent the yields 
of duplicate pots and give an idea of the individual variability in plant production. 
The antagonism obtaining here is clearly very marked. 
Series IX 
CUSO4 versus NaCl — Oakley Soil 
NaCl .4 percent constant — CUSO4 varying 
Table XII gives the results obtained and other necessary data in 
regard to Series IX. The Oakley soil used in this case was different 
from any of the lots used in the other series described in this paper and 
hence gave very different yields in all the pots. The figures submitted 
