152 EXPERIMENT STATION. [Jan. 



The resistances in Table V. were taken in March and repre- 

 sent considerablj higher readings than those given in the pre- 

 ceding tables, although there the distance between the electrodes 

 was 10 feet, while in the readings shown in Table V. the dis- 

 tance was only 8 feet. The higher resistance is due, as shown 

 in this table, to the cutting away of some of the outer tissue 

 around the electrodes, a feature which will be discussed later; 

 and also in part to the measuring of the resistances in March 

 instead of in April, May and June, as w^as the case with the 

 preceding observations. 



The results obtained from these readings, however, are some- 

 what similar to those given in the preceding tables ; the highest 

 resistance occurring on cold days and the lowest on warm days. 

 The highest resistance shown in any one observation was on 

 March 21, at 8 a.m., on the north side of the tree. The temper- 

 ature for this same period was 36.5° F., which is one of the 

 lowest recorded. The lowest resistance was on the 24th of 

 March, at 4 r.:M., on the east side of the tree following one of 

 the high temperature periods. The highest average resistance 

 for any single day occurred March '18, and this coincides with 

 the lowest average temperature. The lowest average resistance 

 for any single day occurred March 24, followed by March 27, 

 which were the two warmest days. The average temperature 

 records for both days, taken at the time of the observation, was 

 as follows: March 24, 52.5° F., the average temperature for 

 the 27th being 57.3° F. The mean temperature (maximum and 

 minimum) on this date was 38, and that for March 27 was 41. 

 By referring to Table VI. it will be observed that March 24 

 was clear and sunshiny, with the wind southwest, and March 

 25 was fair and warm, and occasionally cloudy, with no wind. 

 The average resistance for all periods was the greatest in the 

 morning, followed by those giv(>n at 12 m. and 4 p.m. At 8 

 A.M. it was 02,042, at 12 m., 43,880, and at 4 p.m., 38,040 ohms. 



