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BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE 



A general view of the experimental field as it appeared on May 8, 

 1918, is shown in Figure 1. 



After the 1918 crop was harvested, measurements of the charge 

 carried by the wind were undertaken. A flame collector was used, 

 which was connected to the gold leaf of an electroscope, the case 

 being grounded. A full-scale deflection of 25* divisions represented 

 a potential of about 1,000 volts. In all the measurements the 

 collector was held at a height of 1 meter above the ground. 



A light south wind was blowing the day the measurements were 

 made. With no charge on the network, a very slight deflection of 

 the gold leaf could be noticed. With the network charged, however, 

 the full-scale deflection occurred very rapidly at any point under and 

 within 20 feet outside the network on all sides, even to the south, 

 the direction from which the wind was coming. At 50 feet south, 

 only about 1 division deflection was obtained. North from the net- 

 work the deflection to full scale was slower and more irregular the 

 greater the distance from the network, and when only 2 feet south of 

 the screen along the south side of the north plat the maximum deflec- 

 tion obtainable was about 20 divisions. Just north of the grounded 

 screen the maximum deflection obtained was about 9 divisions. As 

 the collector was moved farther north from the screen and into the 

 control plat, the deflection again increased, until at the center of the 

 control plat it was off the scale again. The grounded screen along 

 the south side of the control plat thus afforded little protection from 

 the drifting charge. At a point 1,000 feet from the network, the 

 last point observed, a full-scale deflection w r as obtained. At all 

 points beyond 100 feet from the network over the south plat the 

 deflection was very irregular and unsteady. 



The Weather Bureau records show that during the 46 days of 

 treatment in 19.18 the wind was due south only 3 days. Owrng to 

 the distance of 350 feet between the treated and control plats, the 

 wind would have to be nearly due south to carry any appreciable 

 charge over the control plat. 



SUMMARY OF EXPERIMENTS IN SECTION E 



The relative yields of the south (treated) and north plats in section 

 E are summarized in Table 7. 



Table 7. — Summary of yields of rye and winter wheat on the south (treaied) and 

 north (untreated) plats, section E, Arlington Experiment Farm, in six stated 

 years 



Year 



Crop 



Treatment 



of south 



plat 



Ratio of yields of 

 south to north plats 



Year 



Crop 



Treatment 



of south 



plat 



Ratio of yields of 

 south to north plats 





Total 



Grain 



Total 



Grain 



1913 



Rye 



Wheat... 

 ...do 



None 



Positive 



...do 



0.98 

 1.02 



1. 14 





1916 



1 1917 



1918 



Wheat... 



...do 



...do 



Negative... 



None 



Positive 



1.03 

 1.04 

 1.07 



0.89 



1914 



1915 



0.97 

 1.03 



.95 

 1.02 



It is evident from the summary that the electrical treatment did not 

 produce any sensible increase in yield. An examination of the detailed 

 results for 1915 shows that the somewhat higher ratios obtained (lur- 

 ing this unfavorable year are due to a marked decrease in yield in 



