INFLUENCE OF THE ALKALI SALTS UPON THE GROWTH OF RICE PLANTS. 293 
the decreasing toxicity of the mixtures 15 upon the duration of life of 
Ruppia maritima is as follows : 
1. NaCl 
2. NaCl + KC 1 
3. NaCl + MgCl 2 
4. NaCl + CaCl^ 
5. NaCl + KC 1 + CaCl.j 
6. NaCl + KC 1 + CaCl 3 + MgCl 3 + MgS 0 4 
7. Sea water. 
The subject seemed to us to be of much importance as well as of 
interest for the solution of the question of alkali soils. We have there- 
fore selected chloride of sodium, potassium, magnesium and calcium as 
the salts to be tested and the experiments were conducted as follows. 
Thirty four beakers of about 5.5 cm diamenter and 7 cm. deep, each 
containing 30 cc of culture fluids, served for the experiment. Thirty 
three beakers received the solutions noted in the tables below while one 
beaker containing distilled water served as control. The seed of almost 
uniform size and specific gravity were germinated in glass dishes holding 
distilled water. When the plumules were about 10-20 mm. long five 
seedlings, after being washed several times with distilled water, were 
transferred to each of the culture beakers and kept in a green house. 
The beakers were then covered with glass plates to exclude dust and 
retard evaporation as much as possible. The evaporated water was supple- 
mented with distilled water from time to time to keep the solutions 
always in their initial concentrations. The measurement was made when 
the difference in development in the respective culture was strikingly 
noticeable. The results were as follows. 
i ) Each salt in the mixtures was mixed according to the amount of V a n ’ t Hoff’s formula 
of artificial sea water as follows : 1000 cc. NaCl 3111/8 ; 78 cc. MgCl2 3m/8 ; 38 cc. MgS 0 4 
3m/8; 22 cc. KC 1 3m/8; 10 cc. CaCl 3 3m/8. 
