^)vi^f^4^ r\/^^(^ 



/V*— *— " 



1 P.M. 2 P.M. 



^0. 5. Variation in positive potential due to the clouds of dust raised by traffic on the roads. 



1 P.M. 



No. 6. Taken simultaneously with 5. 



2 P.M. 



1 P.M. 



No. 7. Taken simultaneously with 5. 



V 



2 P.M. 



1.30 A.M. 10.30 A.M. 



No. 8. Variation in potential due to steam from passing trains. 



