BEHAVIOR OF PLANTS IN UNVENTILATED CHAMBERS 285 
by exact experiment. A narrative of such experimentation is given 
in the following pages. 
Experimentation 
Growth of Plants in Unventilated Small Chambers 
Series I. — The test for this series was made with plants confined 
under glass bell jars or under zinc cylinders closed atone end, bell jars 
and zinc cylinders having a capacity of 6 to 15 liters each, according to 
the size of the plants to be covered, and all placed in a darkroom of 
about 12 cubic meters capacity. For the standard, an equal number of 
plants of the same species were grown in uncovered pots in the same 
darkroom. An electric blower was employed to send day and night 
the air of the dark room in a gentle current over both sets of prepara- 
tions. The temperature over the uncovered plants varied from 21° 
to 24° C; in the bell jars and metal cylinders it was usually one 
degree higher by the thermometer, the difference in the showing of 
the thermometer being due probably to the current of air. The 
humidity over the uncovered seedlings varied from 35 percent to 58 
percent; under the covers it stood near 100 percent. 
The most of the work was done with seedlings, as seedlings are 
usually the plants employed for darkroom work. The seeds were 
planted in sphagnum moss in pots, and, as soon as the seedlings 
appeared above the moss, half of the pots were placed under the 
covers while the other half were exposed to the air current. 
Observations and records were made every day through the period 
of the tests which varied with different sets from 5 to 17 days. The 
points for which observations were made were size of plants, time of 
unfolding of leaves, size of leaves, time of falling over of the seedlings, 
and general appearance. 
The species and varieties of seedlings employed, with the numbers 
of plants, were as follows: Zea mais L. 140, Zea mais var. everta 
Sturtev. 54, Raphanus sativus L. 31, Fagopyrum esculentum Moench. 
25, Pisum sativum L. 65, Lupinus alhus L. 19. 
Observation and measurements showed but slight differences 
between the plants raised under the two conditions. Members of the 
laboratory staff were asked to tell the differences between the two 
sets of plants when the pots were placed in two groups on a table, 
but were never able to name distinguishing features unless the com- 
parison was made at a time near that of the exhaustion of the seedlings. 
