5388 The Philippine Journal of Science 1920 
culture solutions the plants were about five days old. They were 
grown in the culture solutions, renewed every four days, for 
twenty-four days, except in the case of series III and IV in which 
the growth period was extended to thirty-two days. 
At the end of the growth period the plants were harvested 
for the determination of their dry weight. Notes were made 
at this time of the appearance of the tops and roots, special 
attention being given to apparent pathological conditions that 
might indicate injury from unbalanced salt nutrition. The 
tops and roots were harvested separately, the roots being severed 
from the tops at the point of attachment of the seed.*® The 
tops and roots were dried separately for about two days, at a 
temperature of 102-105° C., to approximately constant weight, 
and the dry weights were then determined. 
The experiments were conducted in one of the greenhouse 
rooms of the Laboratory of Plant Physiology, on the outskirts 
of the city of Baltimore. The evaporating power of the air 
for the period of each experiment was determined by means 
of Livingston white spherical porous-cup atmometers,*” one of 
the instruments being operated on each of the rotating tables. 
The atmometer bottle was placed 10 centimeters from the center 
of the table, the top of the sphere being 40 centimeters above 
the table top. The atmometers were read every four days, 
when the solutions were changed. A record of fluctuations in | 
temperature was obtained by means of a Richard thermograph 
placed in the shade near the plants. 
SERIES I 
METHODS OF SERIES I 
Series I was continued for twenty-four days, from January 
11 to February 4, 1916. During this period the highest air tem- 
perature was 29° C., on January 26, and the lowest was 10° C., 
on January 17. The average daily maximum temperature for 
the period was 25° C., and the average daily minimum 18° C. 
The mean daily water loss from a white spherical porous-cup at- 
mometer, indicating the evaporating power of the air, was 17.2 
; * The seed-coat remnants were dried and weighed with the roots; Shive 
discarded them. 
“ Livingston, B. E., Atmometry and the porous cup atmometer, Plant 
World 18 (1915) 21-30, 51-74, 95-111, 143-149. Also reprinted, Tucson, 
Ariz, (1915). 
