12 Professor Gardner on the Influence of the Dew-point 



After a delay of 12' the caoutchouc bag was used and tied 

 tightly around the stem, and after 1 7' the bag was pierced 

 by the electric pair, the results being, — 



Beyond this period it is impossible to examine the gauge, for 

 the included stem begins to give off gas into the water, and 

 therefore partially arrests the ascent of the coloured fluid. 



Table I. 

 June 15th. Experiment as before, time of collection 9 h 35'. 



The coldness of the fruit in the three first measures of the 

 table I. was due to the presence of a little external moisture, 

 and the greater temperature of the room than the external 

 air. 



In both these tables the effect of arresting the evaporation 

 is extremely apparent by an elevation of 8^° and 16 0, 6 re- 

 spectively ; it is to be observed, however, that the drying power 

 given in the two additional tables represent the external and 

 not internal measure; the saturation within the caoutchouc- 

 bag being probably greater. In the table H. there is another 

 coincidence worthy of remark, the gauge marks a decreasing 

 power of suction on the part of the apple as its temperature 

 increases and the evaporation decreases, showing a compen- 

 sation between the amount of perspiration of the leaves and 

 fruit and the supply of fluid. 



Without detaining the reader, it appears that the foregoing 

 tables prove, — 



1st. That the temperature varies with the drying power. 



2ndly. That the amount of evaporation and its effects in pro- 



