Influence of Aeration of Nutrient Solution. 191 
60 per cent. Up to the twenty-fourth day after sowing no 
difference was obvious, but by the twenty-ninth day the difference 
began to appear and steadily increases. In other words the 
difference begins to appear with the fifth leaf. 
A similar improvement was observed in the dry weight at 
the end of the period. The figures obtained are shown, together 
with probable error in each case. 
Aerated. 
Non-aerated. 
Shoot 
0-943 
0-585 
Root 
0-217 
0-128 
Total . 
1-160 + 0-035 
0-713 + 0011 
This gives an increase in dry weight resulting from aeration of 
63 per cent., many times greater than the probable error. 
Series 2. 
The food solution used in this series consisted in a modification 
of Crone’s solution, namely 
Potassium nitrate 
1-00 
gm 
Magnesium sulphate (cryst.) 
0-25 
Calcium sulphate 
0-25 
>> 
Potassium monohydrogen phosphate ... 
0-25 
Ferric chloride 
0-10 
>> 
Tap water... 
1000 0 cc. 
This series ran contemporaneously with Series 1, but the 
solutions were left unchanged through the whole growth period. 
The culture jars were however filled up with water towards the 
end of the experiment, namely on June 16, the 45th day after 
sowing. 
Similar results were obtained as in the case of Series 1, both 
in regard to leaf development and dry weight after 50 days, The 
numbers actually obtained were as follows : 
Days after sowing 
Number of Leaves 
Aerated 
Non-aerated 
8 
20 
2-0 
17 
3-0 
3-0 
24 
4-0 
40 
29 
5-3 
4 9 
33 
6-1 
5-6 
35 
7-6 
61 
37 
8 3 
6-7 
41 
11-3 
8-5 
43 
13-3 
9-6 
45 
14-8 
10-9 
48 
171 
12-0 
50 
18-3 
12-7 
