1908] BRIEFER ARTICLES 227 
absorbed by the quartz was found to be about 10 per cent. in ppm of the 
original quantity. It was determined in the following way. The basket 
with the sand was removed from the jar. A sample was immediately taken 
to determine the water content; at the same time another portion of the 
same sand was washed with distilled water in ten successive portions. The 
Washings were then evaporated to the volume calculated from the results 
obtained with the first sample (per centage of moisture in the sand) and the 
phosphates in the liquid determined. The phosphates in the extract con- 
tained in the jar from which the basket was removed were also determined, 
for pe : Be 
or 7 days with P.O, solution (Z, 10,000PP™; 2, 7000PP™; 3, BoooPP™); middle 
» left to right, watered in same way (I, 5000PP™; 2, 4oooPP™; 3, 3000PPi); 
: left to right, watered during all 29 days (Z, 2000PP™; 2, roooPP™; 3, dis- 
tilled water). ' 
and the difference between these determinations taken as the amount of 
Phosphates absorbed by the sand. 
a tolerance of the wheat seedlings to concentrations of the phosphate 
. “ry much increased when grown in the soil proper, as shown y ig. J: 
and (eo eenttations of 6000PP™, as seen also from the columns of “green 
a air-dry” weights in Table A, had no injurious effect on the plants. 
Y 4 concentration of 10,000PP™ was distinctly harmful. 
The addition to the soil of unsterilized, fairly well-rotted cow manure, 
. 
