ge, | 
1904] BRIEFER ARTICLES 69 
have an end diameter of 40°™ and a height of 7o°™. After a number of 
holes had been bored in the sides and bottom, each of these was placed 
upright, with the top even with the general ground surface, in gravelly 
sand of an ancient lake beach in the experiment grounds of this laboratory. 
The barrels stand in a north-and-south row about a meter apart, the finest 
soil being at the southern end of the row, the coarsest at the northern. 
Each barrel was filled to the brim with its particular grade of culture soil, 
the salts being added in solution as the sand was shoveled in. The soil in 
and around the barrels was then thoroughly soaked with water. After the 
Fic: 2: 
soils thus prepared had stood several days, wild plants were dug in the 
Vicinity of the university and set out in the cultures, practically all of the 
soil adhering to their roots having first been removed by gentle water- 
washing. 
Similar plants, from the same locality, and often from the same clump, 
were chosen for the cultures. Immediately following the planting, suffi- 
cient water to wash the soil closely around the roots was added and no 
subsequent watering was done. The plants used are as agape eg 
compressa, Poa pratensis, Potentilla anserina, Potentilla argentea, Solidago 
serotina, Helianthus strumosus, Helianthus divaricatus, Verbena stricta, 
and Verbena hastata. 
Placed in the open, as the cultures are, they have been subjected to 
the same external moisture conditions both in regard to precipitation and 
