6 
Bouyoucos, Transpiration of Wheat Seedlings as Affected etc. 
Each basket within tbe sarne density, and each gToup of 
baskets representing the various concentrations, bötb in the sand 
and soil cultures, contained at each time, exactly the same amount 
of sand or soil, and exactly the same percentage of moisture content. 
The moisture content was bronght up to the desired point by the 
addition of the nutrient solution, and then kept at that point 
throughout the duration of the experiment, by the addition of 
distilled water. 
* 
All the experiments condncted at the different periods always 
received the same density of the same complete nutrient solution. 
The composition and preparation of the latter are shown below. 
Calcium Kitrate 
27.0 
grams 
Magnesium Sulphate 
6.0 
n 
Potassium Phosphate (Monobasic) 
15.0 
Ferric Sulphate 
0.5 
Potassium Chloride 
7.5 
Total 56.0 grams 
These salts were dissolved in 10 liters of distilled water. 
In order to avoid as mnch precipitation as possible, they were 
dissolved in the following manner and then mixed together. 
Ca(Ko 3 ) 2 plus KCL dissolved in 3 liters of water. 
MgS0 4 plus Fe 2 (S0 4 ) 3 dissolved in 3 liters of water. 
K 2 HP0 4 dissolved in 3 liters of water. 
They were then brought together and the volume made up to 10 liters. 
Even when the above precautions were taken, some preci¬ 
pitation did take place and the solution had to be filtered through 
ordinary fllter paper. The density of the filtrate was then deter- 
mined by evaporating 50 cc. of the solution and weighing the 
residue. This gave 4500 parts per million. From this stock 
solution, the different densities needed for the experiments were 
prepared. These various concentrations with their strength in P. p. m., 
and in electrical resistance as determined by the Wheatstone bridge, 
are shown herewith. 
Density in P. p. m. 
Density in Ohms 
4500.0 
66.0 
2250.0 
121.1 
750.0 
327.4 
375.0 
588.3 
187.5 
1115.5 
93.5 
2775.0 
0.0 
10000.0 
Each experiment was continued for three weeks. Düring this 
period, the daily development and general appearance of the plants, 
