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During the experiment the apparatus rested on some bricks, so 
that it was about 20 cm. from the ground. 
Experiment I. 
Apple tree . 
The ice apparatus was fixed round the trunk having a diameter 
of 3 1 /, cm., of a small apple tree, about 27< metres high, on July 
21 st 1904, at noon, the weather being hot and sunny. The apparatus 
was filled with ice and in the course of the afternoon the temperature 
in the space round the trunk fell to about 1° C.; not the slightest 
fading of the leaves could be detected, although such fading would 
have at once been noticeable by comparison with two other apple 
trees which stood next to the tree experimented on. 
Nor could any change be observed on the following days. The 
temperature of the air space round the stem remained continuously 
between 0° and 3°. 
The maximum temperature of the atmosphere on the days of the 
experiment oscillated between 23° and 29°. 
On the sixth day, when the temperature of the atmosphere was 
20° and that round the trunk 0°, an strong transpiration of the 
leaves was demonstrated by means of the cobalt test. On the seventh 
day the trunk was sawn through immediately above the ice apparatus; 
a hole was drilled in the portion of the trunk still inside the apparatus, 
and a thermometer was placed in it. 
In this way I was able to show that the temperature inside the 
trunk was the same as that of the annular air space round the trunk , 
i.e. in the course of three hours it oscillated between 2° and 3°, 
while the temperature of the atmosphere was 24° to 25°. 
Experiment II. 
Polygonum cuspidatum. 
The ice apparatus was fixed round two immediately adjoining 
stems, 2 metres in height, on July 6 th 1905, at noon, and it was 
filled with ice. In the course of the afternoon the temperature in 
the air space round the stems fell to 0°, without withering taking 
place. The numerous stems surrounding the apparatus served as 
controls. Nor was any change noticeable during the following days. 
The temperature round the stems remained continuously between 
0° and 3°. The maximum temperature of the surrounding atmosphere 
