70 BOTANICAL GAZETTE [JULY 
absorption from the surrounding natural soil. At the time of placing the 
barrels, the ground water of the ridge where they were sunk had its sur- 
face at a depth of 2.2™, 7. e., 1.5™ below the bottom of the barrels. Thus 
the three cultures present no differences either in external water or in 
chemical nature, but differ only in size of their component quartz particles. 
It need hardly be added that the gravelly sand surrounding the barrels is 
perfectly uniform throughout the series. 
Fic. 3: 
: The cultures were started May 5, 1904. For the first few days no 
—— was to be noted in the growth of the plants, but oradually those 
in the finest sand forged ahead of the others, and se task 5a difference 
was very well marked. The plants in the finest material showed a much 
greater growth and a greater general thriftiness of vegetation. The photo- 
a betas exhibit clearly the relation between the three cultures 
Sine ns es ies J mia ee Fig. t shows the condition of the culture in 
> fig. 2, that in medium sand; and fig. 3, that in coarse sand. 
The following table show i 
Ss the h = ese he 
three cultures on June 1 5. eight in centimeters of the plants in t 
