WISLIZENUS — ATMOSPHERIC ELECTRICITY. 531 



in 1863. This may prove to be an eleven years' period, re- 

 lated to the same periodicity of terrestrial and solar magnet- 

 ism. 



The cause of atmospheric electricity has always been a 

 perplexing question, and is by no means solved yet. As its 

 causes have been supposed the force of wind, the evapora- 

 tion of water from the earth and sea, the chemical processes 

 constantly taking place on our globe, the act of vegetation, 

 the conflict between polar and equatorial currents of air, the 

 combined action of temperature and humidity, etc., — most of 

 these supposed causes exercise no doubt an indirect, partial 

 and modifying influence on development and distribution of 

 atmospheric electricity, but none of them seem to be ade- 

 quate to account for the regular and continuous streams of 

 electricity in our atmosphere. 1 am inclined, therefore, to 

 look hypothetically for a more direct cause of atmospheric 

 electricity in terrestrial and solar magnetism. The science 

 of terrestrial magnetism is as yet in its infancy, but enough 

 is already known to prove the existence of such a force. The 

 aurora borealis is now generally considered an electrical phe- 

 nomenon, produced by accumulation of magnetic force near 

 the magnetic poles of the earth. During an aurora electric 

 currents are developed on telegraphic wires, sufficient to 

 serve as a substitute for the ordinary voltaic battery. From 

 pole to pole, as Lamont has proved, electric currents are con- 

 stantly flowing on the earth's surface, while others are circu- 

 lating from east to west. There is the same periodicity in 

 atmospheric electricity and terrestrial magnetism every day 

 — two maxima and two minima, two daily ebbs and floods — 

 and longer observation will very likely constitute also an 

 eleven years' period for atmospheric electricity, as it has been 

 proved for terrestrial and solar magnetism — reasons enough 

 to believe in a direct connection between terrestrial magnet- 

 ism and atmospheric electricity. 



The physiological effect of electricity on organic bodies 

 may generally be called stimulating. If the air we inhale 

 contains a good deal of positive electricity, as it happens in 

 cold, dry weather with clear sky, we feel a bracing, invigor- 

 ating effect from it, and on hot, sultry days without any 

 electricity, a feeling of depression. But as the meteorologi- 

 cal phenomena form a unit, and as we cannot separate the 

 effect of electricity from that of temperature, humidity and 

 barometric pressure, it is difficult to say how much of that 

 feeling is due to electricity or to other qualities of the air. 

 The presence or absence of electricity in the air has there- 

 fore been often overrated, or wrongly commented upon. In 

 cholera epidemics, for instance, diminution or absence of at- 

 mospheric electricity has often been accused of being the 

 cause of this mysterious disease. My observations daring 



