WISLIZENUS — ATMOSPHERIC ELECTRICITY. 



291 



electricity corresponds with the coldest months of the year, 

 and vice versa. Thus the six coldest months of the year, 

 from October to March, give, during the four years, in tem- 

 perature the average mean of 41.1° F., and in positive atmos- 

 pheric electricity the average mean of 11.8 degrees of Dell- 

 mann's electrometer ; while the six wannest months of the 

 year, from April to September, give an average mean of 71.3° 

 F. in temperature, and only 4.5 degrees in electricity. The 

 same rule answers for the average mean of every single 

 month, with the exception of a slight discrepancy between 

 April and October, the temperature of April corresponding 

 better with the electricity of October. 



This coincidence in the inverse rise and fall of the temper- 

 ature and electricity proves certainly some connection be- 

 tween the sun and atmospheric electricity. The light and 

 heat of the sun seem to control the quantitative development 

 and monthly periodicity of electricity in a negative way; 

 that is, when the sun's rays are more powerful, electricity is 

 diminished, and when less powerful, increased. This singu- 

 lar result is probably explained by the fact, that the very 

 months which are our warmest in the year, Aprir to Septem- 

 ber, constitute also the time of aphelion, or greater dis- 

 tance of the earth from the sun ; and our colder months, 

 from October to March, that of perihelion, or less distance 

 from the sun. It appears, therefore, that the monthly perio- 

 dicity of atmospheric electricity is not really caused by the 

 sun's rays, by light and heat, but by the greater or less 

 distance from the sun; and, as the same law holds good for 

 terrestrial magnetism, it confirms my opinion, formerly ex- 

 pressed, that atmospheric electricity and terrestrial magnet- 

 ism are closely allied emanations of the same force, derived 

 in some way yet unexplained from the mass of the sun. 

 Hence this increase in intensity by greater approach to the 

 sun without regard to or notwithstanding the greater light 

 and heat of the sun's rays. If, as I proposed in my former 

 paper, regular observations of atmospheric electricity should 

 be made in the southern hemisphere leading to the same re- 

 sult, this supposition of mine would then be established as a 

 fixed fact. 



Let us compare now the monthly mean of atmospheric 

 electricity Avith that of relative humidity. The monthly 

 mean of relative humidity is by far less regular than that of 

 temperature and electricity, and is in all likelihood not a 

 cause of electricity, but one of its modifying influences, dis- 

 tributing it through the atmosphere and conducting it to the 

 earth. We find therefore, generally, high relative humidity 

 corresponding with diminution of electricity. 



It seems, also, that the direction and prevalence of winds 

 has no direct causal connection with positive atmospheric 



