ART. 7.-Y. HOMMA : 



and also that the rate gradually tends to become iiide])endeiit of the 

 sign of the charge. 



Xow all of the above mentioned theories are based on experi- 

 ments, arid tlie actions or processes contained in them may actually 

 take place in the atmosphere. The only ([uestion is that of the 

 competence. For my part, I feel convinced that friction is by far the 

 most effective cause of electrification. It is my main object here to 

 see hoAv far we can explain the manifold phenomena in atmosj^heric 

 electricity by the friction theory alone. 



EXPERIMENTS. 



First of all, in order to assure myself, how different objects 

 become electrified, I made the f:)l lowing experiments. I took 

 a Kelvin-Mascart's electrometer, 

 whose quadrants were charged 

 by a water battery, the middle 

 ])oint of which was connected 

 with the earth. To the needle 

 was connected one end of a fine 

 wire, the other end of whicli 

 was put on a Mascart's in- 

 sulator. The sensibility of the 

 needle was about 0.17 volt per division of the scale. 



Experiment I. — ^The friction of sand particles with leaves, twigs, 

 wood, etc. These objects were placed one bv one upon the Mascart's 

 insulator, and from a metallic funnel suspended by silk thread, a 

 stream of fine sand Avas poured down against them, so as to electrify 

 them by fricti(3n. In each case, the electrometer showed a positive 

 electrification. These objects were then disconnected from the wire, 

 and held by a separate stand over the insulator. A stream of sand 



???^ 



