158 



EXPERIMENT STATION. 



[Jan. 



It will be seen that these resistances were all ranged between 

 04,000 and G7,000, and coincide very closely with those given in 

 Experiment B. 



Experiment D. 

 Another experiment, using the same branch as was used in 

 Experiment C, was undertaken, but in this case the water in 

 wliicli the branches stood was heated to a temperature ranging 

 from 100 to 130° C. The readings were taken at half -hour in- 

 tervals, with the following results: — 



Ohms. 



67,000 

 68,000 

 67,500 

 67,600 

 73,000 



9.30 A.M., 



10.00 A.M., 



10.30 A.M 



11.00 A.M, 



11.30 A.M. 



12.00 M 



1.00 P.M 



1.30 P.M. 



2.00 P.M. 



2.30 P.M. 



3.00 P.M. 



3.30 P.M. 



4.00 P.M. 



72,000 

 72,000 

 71,000 

 69,000 

 70,000 

 73,000 

 75,000 

 76,000 



The rise in temperature had little or no effect on the resist- 

 ance. On the other hand, the readings in some cases were 

 slightly higher. 



Experiment E. 

 The same branch was used in this experiment. After stand- 

 ing over night and the water brought to room temperature a 

 space of 1/2 inch down to the wood was removed halfway be- 

 tween the electrodes ; in other words, the branch was girdled 

 for this distance. The following readings were obtained : — 



8.30 A.M., 



9.00 A.M., 



9.30 A.M., 



Ohms. 



122,000 

 121,000 

 124,000 



all averaging not over 123,000. The results here show greatly 

 increased resistances as the effect of girdling. 



