]y ART. 7.- Y. HOMMA: 



1. The negative potential observed during strong wind is 

 entirely due to the negative electrification of the dust raised and 

 carried in the atmosphere, by friction with terrestrial objects. 



2. Similarly the high potential observed during fog or haze is 

 due to the positive electrification of the Avater particles composing it. 



3. When a mass of cold air comes in contact with a mass of 

 warm air, the former bec<jmes positively electrified with respect to the 

 latter. This fact is probably one of the causes which determine the 

 normal distribution of the electric field in the atmosphere. Also it 

 may account for the fact that an abnormally high potential is generally 

 accompanied by an abnormally low temperature. 



4. The invariably high potentials at or near sunrise are 

 probably due to the fact that the air lying near the surface has then 

 ;i temperature lowev than that of the air above it, and becomes, in 

 consequence, positively electrified. 



5. When two masses of îiir at different temperatures happen to 



be mixed suddenly, the elecric field is violently disturbed. The 



disturbances are, however, just such as are in accord with the fact 



stated in 3. 



In conclusion, I wish to express my great indebtedness to Dr. K. 



Nakamura, director of the Central Meteorological Observatory, by 



whose kind permission, I have been able to examine several original 



records preserved in that observatory. The copies of photographs are 



also reproduced here through the courtesy of that gentleman. I\ly 



best thanks are due to Professor Tanakadate and to Professor Nagaoka 



of the Tokyo University, who were kind enough to give me valuable 



sufrsfestions, and to favour me with access to the literature of the 



subject. 



Physical Laboratory, First High School. 

 T(3kyo. 

 November, 11)01. 



