RELATION OF TRANSPIRATION TO STOMATA 49 1 
from seed but the plants grew very slowly and were so much stunted 
they they could not be used in this work. Lastly only those plants 
could be used which would attain a fair size and maintain a reasonably 
uniform rate of growth while the experiment was performed. (See 
Table I.) 
2 . Preparation of the Jars 
Most of the plants with the exception of Pelargonium zonule and 
Primula sinensis were started in flats from seeds. While the plants 
were still young they were carefully transplanted into the jars where 
they remained unsealed until they were large enough to use in the 
determination of transpiration. The plants of Primula and Pelar- 
gonium were healthy greenhouse plants which were transplanted 
directly into the jars and then were left on the greenhouse bench for 
several weeks before sealing for the experiment. 
Large stone crocks of two sizes were used for containers; gallon 
crocks were used for the large plants, while one-half-gallon crocks 
were used for the smaller species. On the bottom of each jar was 
placed an inverted three-inch flower pot filled with gravel. Around 
the flower pot about one centimeter of sand was spread over the bottom 
of the jar. A glass tube with a i cm. bore was inserted into the hole 
in the bottom of the inverted flower pot and the tube extended about 
10 cm. above the surface of the paraffin when the jar was sealed. This 
tube was used for watering the plant. The flower pot with gravel 
in it rapidly absorbed the water and the sand spread the water evenly 
over the bottom of the jar. Another tube was put in the jar so as 
to act as an aerating system for the soil when the jar was sealed. 
Then the soil was placed in the jars and the plants were planted in 
them. The number of individuals of each species that were placed 
in one jar varied from one to several, depending upon the size of the 
plants. (See Table L) The cotyledons which still happened to be 
on the plants at this time were removed when they were transplanted. 
After the plants had stood in the jars from one to several weeks, 
and had become well established they were ready to be sealed. The 
kind of seal used is that which was used by Briggs and Shantz (i) 
except that a little harder grade of paraffin was used. A mixture of 
eight parts of about 60° melting paraffin and two parts petrolatum was 
taken; however, the exact proportions were not determined in every 
case. The mixture was heated to melting and was then poured over 
the surface of the soil so that upon cooling it made a perfect seal. 
