[Vor. 7 
310 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
supplied by the Plant Introduction Garden of the Bureau of 
Plant Industry, Chico, California. The corn was a standard 
field strain of yellow Dent. 
The results shown in tables 11 and rr! were obtained at Car- 
mel, California, during July and August of the same year. At 
Carmel the cultures were arranged on lattice tables in the open. 
The average temperature was about 15.6? C. and the average 
daily evaporation from a standard spherieal porous cup at- 
mometer about 15 cc. Table 11 represents cultures prepared 
exactly as in table 1 except that glass beakers, of the same ca- 
pacity, were used instead of tumblers. The data in table m 
are from experiments closely paralleling those represented by 
table 11 except that in the former the containers used were one- 
quart preserving jars (Economy style). This type of jar proved 
most convenient in this work, since the mouth of the jar is large, 
taking the same corks as used in the tumblers and beakers. 
Moreover, the spring clips which accompany these jars afford 
a handy method of fastening the cork to the jar so that the 
seedlings are not readily disturbed. "The use of the larger con- 
tainers in this case explains the larger quantities of salts or 
solutions employed, and, of course, vessels of this capacity per- 
mit the experiments to be continued over a longer period of 
time. 
Inasmuch as certain cultures in each of these series contained 
not only a full mineral “nutrient” solution but also some citrate, 
it seemed well to arrange all the solutions and then let them 
stand two days in case some evidence of fermentation might 
develop. This occurred in certain cases especially in the second 
and third series, but afterwards cleared up. The significance of 
this will be discussed in a later paper in which the physical 
characteristics of nutrient solutions in general will receive special 
consideration. 
In all eases where readily soluble salts were used in these 
experiments the initial quantities in the different series varied 
considerably, as also the quantities added from time to time, 
1 This work was done at the Coastal Laboratory of the Carnegie Institution of 
Washington. The writer is pleased to make acknowledgment of the facilities and 
coóperation extended by Doctor D. T. MacDougal, Director of Botanical Research, 
and of the courtesies of other members of the sta 
