8 AKT. 7— Y. HOMMA : 



Experiment 7//.- Tlie contact of hot and cold air. A piece of 

 lighted candle was placed on the insulator, so as to serve as a 

 collector. When a gas flaîne was brounht near it, the electrometer 

 showed a negative electriticati(Hi, amounting to 10 divisions or more. 

 When, however, the gas was opened unlighted, no electrification was 

 observed. Xot only the gas fiame, but the fiâmes of lamp and candle, 

 and even a heated piece of iron, produced the same eftect of negative 

 electrification. The same effect, thouiih in much less des"ree, was 

 obtained when a current of warmed air was sent against the collector. 

 The o])posite efiect, i.e. j)ositive electrification was obtained, when a 

 current of air cooled by a freezin"* mixture, was l)lown aofainst the 

 collector. These experiments show that when two masses of air at 

 difterent temperatures are in contact with each other, the hotter one 

 becomes negatively and the cooler one positively electrified. In order 

 to verify this rather important conclusion, I caused two adjoining 

 rooms to have temperatures of 10^ and 20° respectively, and placed 

 the candle flame collector on the insulator iust near the connecting- 

 door. On slightly opening tlie door, the flame was at once blown 

 towards the warmer room, and the electrometer showed an increase of 

 potential, which was precisely the result expected. 



Now as is well known, such experiments on statical electricity 

 are usually associated with a greater or less degree of capriciousness 

 and uncertainty, and, I confess, my case was no exception. It must 

 be added, however, that the experiments were repeated over and over 

 again, and that nearly all the eye observations of the electrometer 

 were carried out by my tw(3 assistants, who had not been informed of 

 what I was expecting to obtain. 



EXPLANATIONS OF SEVERAL PHENOIVIENA. 



In explanation of the general distribution of atmospheric elec- 



