BoviE: NON-AVAILABLE WATER IN SOILS 279 
Size, Per cent. 
Gravel, sic ose Coes Pe see Ge Ee eee 2mm. + 
PING WTAVEN Ss Lisle Gare So tet seve ee ee Ue I-2 mm 0.00 
Coarse sand. 2050.48 Cahn eee I-.05 mm 3.60 
Mediumsand 5:05 eAinaih canes Sacto: 0.5~-0.25 mm 20.51 
Fie SAGd, . asc ws irks code en a ee 0.25—-0.I mm 72.402 
Very fine sand..\ 4 os. ceamales wan, oo eee 0.1I~0.05 mm 2.69 
TOGA so hee ets Or ee ae Se ee emetiee 99. 52 
A full nutrient solution was made up as follows: 
Calcium He ee AION 6a Rie SASS 15.83 gm. supers II 
Potagsiiita nitrates odo. cssus Sula scien aa ee ed 3 
Magnesium Ehee MeSOe-FyeO): oo conc s wae cue 6.85 gm = aes. 3 
Potassium: phosphate... .i(4 Sl aacanciee op tay Ereemeemrr os KH2POs 3 
BOta ose Baas ae nc a: Ss en a eee ee 
Water to make 10,000 c.c. of solution. 
This solution gives a concentration of salts equal to 0.2 per cent. 
The same stock solution was used throughout the entire series of 
experiments. To portions of this full nutrient solution, quantities 
of sodium chloride were added so that series of concentrations 
(salts of full nutrient solution plus sodium chloride) of the following 
order were made: 0.2 per cent. (control), 0.225 per cent., 0.25 
per cent., 0.3 per cent., 0.4 per cent., 0.5 per cent., 0.65 per cent., 
and o.8 per cent. In another series, the percentage of the total 
salts in the nutrient solution was increased, so that, without the 
use of the sodium chloride, the following series of concentrations 
were made: 0.2 per cent. (control), 0.25 per cent., 0.4 per cent., 
0.6 per cent., and o.8 per cent. 
The solutions were made upon the percentage basis, because it 
is impracticable, when dealing with selective adsorption and water 
films, to make up solutions in the ratios of their osmotic strengths. 
Moreover, the questions in mind can be answered equally as well 
with simple percentage solutions. 
Sodium chloride seemed a suitable salt to use since it does not 
readily penetrate plant protoplasm and since it ordinarily contains 
no water of crystallization. Further, Briggs’ has shown that 
sodium chloride is but slightly adsorbed by quartz. The series 
without the sodium chloride served as a check on the purely toxic 
effects of the sodium chloride. 
The quartz was wetted with the solution, so that it contained 
a 20 per cent. (20 grams of solution, plus 100 grams dry quartz) 
