6 TRANS. OF THE ACAD. OP SCIENCE. 



communicated to it by the surrounding atmosphere (durch 

 Mittheilung, permanent electricity of contact,) but developed 

 by induction {durch Vertheilung, electricity of induction ;) 

 that is, the natural electricity of the ball, being in equili- 

 brium, is separated by the electrical tension of the surround- 

 ing atmosphere into positive and negative electricity, one of 

 which is attracted to the upper part of the ball and the 

 other repelled to the lower. Atmospheric electricity, in its 

 normal state, is positive. If we expose, therefore, the collect- 

 in^ apparatus to the positively electrified atmosphere, the 

 natural electricity resting in the ball will, at once, be separated 

 into negative and positive ; the negative will be attracted to 

 its upper part and the positive be repelled to the lower. By 

 touching now the stem with the half-moon-shaped piece of 

 brass, the positive electricity is conducted through the wire 

 and the body of the observer to the ground; the negative is 

 left in the ball and measured by the electrometer. It thus 

 becomes apparent, that, when the electrometer exhibits neg- 

 ative electricity in the ball, it indicates positive electricity 

 of the atmosphere, and vice versa. Before this relation was 

 well understood, doubts were expressed by some, whether 

 the electricity were not communicated to the ball by means 

 of the observer from the earth, the electricity of which is 

 generally negative. To ascertain the truth, or fallacy, of this 

 supposition, I made the following experiment : After having 

 made an observation of atmospheric electricity in the usual 

 way, I tried the electricity of my own body ; finding none 

 therein, I isolated myself perfectly, also the collecting appara- 

 tus and its appurtenances, wherever they touched the house, 

 and made thus another observation of atmospheric electricity. 

 The result in quality and quantity of atmospheric electricity 

 was the same in both cases. This experiment proves, that 

 the electricity collected in the apparatus is not obtained di- 

 rectly from the earth, but from the surrounding atmosphere. 

 The fact, also, that within the house no electricity, or at least 

 very little, can be collected by the apparatus, seems to con- 

 firm the opinion, that the electricity is obtained directly from 

 the surrounding atmosphere in a free state of circulation. I 

 will mention, also, on this occasion, that I sometimes used the 

 collecting apparatus in a horizontal, instead of the vertical 

 position, and obtained invariably the same result. 



The subject of atmospheric electricity attracted my atten- 

 tion, several years ago, as a part of meteorology not suffi- 

 ciently explored. Looking over the long list of the names of 

 those who, during a century, had distinguished themselves in 

 exploring the laws of electricity, I felt somewhat timid in 

 undertaking, what so many intelligent men of science had 

 but partially accomplished; but, considering, on the other 

 hand, that regular daily observations of atmospheric electri- 



