June, 1922] 
MUENSCHER — ABSORPTION OF SALTS 
distilled water every two or three days, and the solution was changed every 
fifth day. At the end of five weeks all cultures were taken down and the 
green weight, dry weight, and ash weight were determined for the tops and 
roots of each culture. After the dry weights had been determined, the 
tops and roots were incinerated in an electric furnace to determine the total 
ash content. The ashing was made at a low red heat for several hours. 
This furnace carried a load of eight crucibles at a time. In order to reduce the 
error due to the method of ashing, each load consisted of one crucible contain- 
ing the tops and another containing the roots of one culture from each of the 
four conditions under which the cultures were grown. 
Winter Series 
The materials and methods employed in the winter series were the same 
as those employed in the summer series. The plants used in this series 
came from the same lot of seed as was employed for the summer series. 
Two solutions were used, one a dilute Knop's solution (0.07 percent) and 
the other a concentrated Knop's solution (0.28 percent). After these cul- 
tures had remained upon the greenhouse bench for one week, all those which 
did not contain four healthy plants were discarded, and the rest were di- 
vided into three groups and placed under the following conditions : 
e. Sunlight; dilute Knop's solution (0.07%) 
/. Shade tent; dilute Knop's solution (0.07%) 
g. Sunlight; concentrated Knop's solution (0,28%) 
These cultures were grown for five weeks, from January 19 to February 
24, 192 1. During this time the water lost by transpiration was replaced 
with distilled water every two or three days, and the solution was changed 
every fifth day. At the end of five weeks the cultures were all taken down, 
and the green weight, dry weight, and ash weight were determined for the 
tops and roots of each culture. 
Data and Discussion 
Summer Series 
Dry-Humid Cultures 
Table i presents a summary of the data obtained from the cultures in 
which transpiration was varied by changing the atmospheric humidity of 
the chambers in which they were grown. The plants in the humid chamber 
were slightly taller anid their leaves were slightly longer than those in the 
dry chamber. The roots of the plants grown in the dry chamber were on 
the average about six centimeters longer and branched more profusely 
than those of the plants grown in the humid chamber. The total green 
weight was slightly greater in the plants grown in the humid atmosphere, 
probably because of the greater quantity of water in their tissues. The 
