416 



TRANS. OF THE ACAD. OF SCIENCE. 



V. — The relative proportion of Positive Electricity, of Negative Elec- 

 tricity, and of no Electricity, in my observations. 



8,388 



. . 355 



. 2,143 



REMARKS. 



The daily as well as the monthly periodicity of positive 

 atmospheric electricity is as apparent in these observations 

 of five years as in the former ones; but a new peculiarity is 

 manifested in them by the gradual diminution in the annual 

 mean of positive atmospheric electricity, and by the annual 

 increase of observations exhibiting no electricity at all. 

 May not this peculiarity give us, perchance, a clue to the 

 annual periodicity of atmospheric electricity ? If my sup- 

 position should prove correct, that atmospheric electricity 

 is closely allied with and principally caused by terrestrial 

 and solar magnetism, we may expect also a corresponding 

 annual periodicity with that higher force. Professor Wolf 

 in Zurich has, after laborious researches, calculated the aver- 

 age periodicity of the declination of the magnetic needle 

 and of the solar spots at lljL years; and while the maxima, 

 according to his calculation, are in our times represented 

 by the j^ears 1837, 1848, 1859 and 1870, the minima coincide 

 with 1843, 1854 and 1865. It is therefore a possibility, that 

 the great falling off in positive electricity in 1865 may rep- 

 resent the lowest point in the wave-like line of annual peri- 

 odicity from 1859 to 1770. For the present I consider this 

 view as merely hypothetical, but observations, continued 

 about five years longer, will prove its fallacy or correctness. 



