16, 5 Espino: Salt Requirements of Young Rice Plants 479 
practically the same for all the cultures of any single series, and 
they were the same for all series that were carried out simul- 
taneously (see dates given in Table 3). To approach practical 
uniformity among simultaneous cultures, the culture bottles were 
placed on motor-driven rotating tables such as were used by 
Shive (1915). The tables stood in one of the greenhouse rooms, 
being located as those of Shive had been. 
During the course of each culture series records of the air 
temperature in the greenhouse in which the cultures were carried 
out were obtained by means of a thermograph in the shade, un- 
der one of the rotating tables. Daily records of the evaporating 
power of the air and of radiation (sunshine) were also made, 
by means of the radio-atmometer (white and black spheres) .*° 
These records will serve to show, in a general way, the temper- 
ature, the moisture, and the total radiation conditions for each 
experiment series. 
PLANT RECORDS 
For some cultures the volume of solution remaining in the 
culture bottle at each solution renewal was measured, and the 
volume absorbed by the plants for the preceding period was de- 
termined. Finally, from these determinations was obtained the 
total volume of solution absorbed by the plants for the entire 
three-week period. This may be taken as practically the same 
as the total volume of water transpired during the period. 
At the end of the experiment period each set of cultures was 
separated into three groups representing good, medium, and poor 
growth, respectively, and a representative from each group was 
photographed. Notes on the appearance of the plants and the 
mean lengths of tops and of roots were approximately determined. 
The plants were then removed from the stopper, the remnant 
of the seed was discarded in each case, and the tops were severed 
from the roots at the point of attachment to the seed. The dry 
weights of tops and of roots (the six plants in each culture being 
treated as a whole) were then obtained in the usual way, the 
drying being done finally at a temperature of about 105°C. 
In some cases the green weights of tops were approximately 
determined, to obtain information on the water content, ete. 
The severed tops from each culture were immediately transferred 
into a test tube which was then closed and stored in a refrig- 
erator until weighing could be accomplished, which in this case 
“ Livingston, B. E., Atmometry and the porous cup atmometer, Plant 
World 18 (1915) 21-80, 51-74, 95-111, 143-149. 
