Atmospheric Electricity. 459 



It will be noticed that the effect of a shower is to make 

 the succeeding readings positive; and generally it is found 

 that negative readings are got only when the ground is drv 

 and also warm ; for on a bright morning the readings become 

 negative earlier than when the morning is cloudy. 



In September there were negative readings on 13 di 

 almost entirely during bright fine weather. 



Table III, 

 Observations at 10 hours M.M.T. September 1884. 



avs 





Electro- 



Percentage 



Wind- 

 direction. 



Rain in 





Date. 



meter- 

 readings. 



of satura- 

 tion. 



past 24 

 hours. 



Remarks. 





- 







inch. 





1. 



4-27 



85 



S.S.W. 





0*16 in. rain fell on August 31st. 



2. 



-16 



44 



w. 







3. 



-95 



45 



W.N.W. 







4. 



-72 



47 



W.N.W. 



f 



Shower at 4 p.m. 



Evening thunder-storm, with 



5. 



-12 



56 



W.N.W. 



007 \ 



heavy rain at sea 12 miles off 

 Madras. 



6. 



? 



62 



W. 



062 





7. 



+ 2 



56 



W.N.W. 





Negative reading at 11 a.m. 



8. 



- 3 



56 



W. 







9. 



- 8 



50 



N.N.W. 







10. 



-17 



48 



N.W. 







11. 



+32 



55 



N. 







12. 



4-27 



51 



N.N.W. 







13. 



+24 



78 



S.W. 



0-59 





14. 



+ 7 



69 



W.N.W. 



r 



Rain and thunder in early 



15. 



+47 



84 



W.S.W. 



1-01 \ 



morning. Thunder-storm at 

 night. 



16. 



+40 



79 



W.S.W. 



1-85 





17. 



+23 



68 



W.S.W. 



0-40 





18. 



? 



77 



W.S.W. 



0-16 





19. 



+29 



61 



W.N.W. 



0-09 





20. 



? 



62 



W. 



011 





21. 



- 4 



60 



w. 







22. 







68 



W.S.W. 





Negative reading at 11 a.m. 



23. 



-33 



66 



w. 







24. 



- 9 



58 



w. 







From September 24, 1884, to May 14, 1885, only one nega- 

 tive reading has been obtained in fine weather. 



Looking over the tables of electrometer-readings, the first 

 feature that strikes one is that in only one case is the potential 

 negative before 9 a.m. ; and that in most cases, if the poten- 

 tial is positive at 10 a.m., it remains positive all day, though 

 on one or two occasions when a low positive reading was 

 obtained at 10 a.m., a negative one was obtained at 11 or 12 



