3*8 
K. MI VA Kl'.. 
Summary. 
From a consideration of the results above tabulated, we may summa- 
rize as follows. 
1) A mixture of three salts which are individually poisonous in like 
concentration produces generally a medium in which the plants grow more 
favorably than in that of two salts. This might be attributed to the fact 
that a mixture so formed approaches nearer to a balanced solution than a 
mixture of two salts. 
2) In a mixture of three salts, the growth of the plants varies with 
the kind of salts. The combination (NaCl + KCl + CaCl.j) seems to be 
superior to (NaCl + MgCl a + CaC! a ) or (KCl + MgCL + CaCL), while the 
latter two, in turn, appear to be better than (NaCl + KCl + MgCU). 
3) The effect of the addition of a third salt seems to be great in 
the case in which the valency of its cation is different from that of the two 
salts already present in solution. On the contrary, the effect seems to be 
little when the valency of the cation of the third salt is similar to that 
of either of the two salts already present. For example, in the case of 
the combination (NaCl + MgCl 3 + CaCl 2 ), when we add NaCl to the 
mixture of (MgCl 2 +CaCl. 2 ) the effect of the addition of a third salt (NaCl)- 
is great, but cn the other hand, when we add MgCl., or CaCl., to the 
mixture of (NaCl + CaCl 3 ) or (NaCl + MgCl 2 ) the effect of the addition 
of a third salt is little. Similarly, in combination (NaCl + KCl + MgCl.,) 
the effect of the addition of a third salt is great when we add MgCI 3 to 
the mixture of (NaCl + KCl), while a marked effect is not observed when 
we add NaCl or KCl to the mixture of (MgCl, + KCl) or (MgCL + NaCl). 
4) Each salt in a mixture of three salts must be present in certain 
suitable proportion for the most favorable growth of the plants. In general, 
in combinations of (NaCl + KCl) and MgCl 2 or CaCL the growth of the 
plants is most favorable in the mixtures with large amount of NaCl and 
KCl and small amount of MgCL or CaCl.^. So also in combinations of 
