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XXXIX. On the state of Static and of Dynamic Electricity during 

 several heavy Showers observed at Brussels on the 14/A of June 

 1852. By A. Quetelet, Membre de V Academic Royale de 

 Belffique*. 



I KNOW but few observations made simultaneously during 

 rains and storms on the static and the dynamic electricity of 

 the air. These two meteorological elements are, notwithstanding, 

 of the greatest importance, and rarely march together ; that is 

 to say, dm-ing powerful electric tensions it often occurs that no 

 current is observed ; and, on the contrary, very decided currents 

 sometimes exist while the electrometer exhibits nothing extra- 

 ordinaiy. 



The showers of which I am about to render an account have 

 presented some peculiarities which appear to me to be worthy of 

 attention. The dynamic electricity was observed by means of a 

 very sensible Gourjon's galvanometer ; one of the wires was con- 

 nected with the earth, and the other with a conductor placed on 

 the roof of the observatory. The static elcrtricity was observed 

 by means of the atmospheric electrometer of Peltier ; the obser- 

 vations were made on the summit of one of the turrets of the 

 observatory, and on a small platform placed at an altitude higher 

 than the surrounding objects. 



On the 14th of June 1852 it had rained at different intei-vals 

 during the morning ; 2"55 millimetres of water were collected. 

 Towards noon thick clouds floated in the inferior regions of the 

 atmosphere, between which portions of the heaven and of cumuli 

 were visible, whose splendid white contrasted with their gray 

 and slightly copper-coloured hues. The Centigrade thermo- 

 meter marked 13°-6 and the barometer 739"73 millimetres. The 

 pressure of the atmosphere was passing a state of minimum at 

 the time. The direction of the clouds, in accordance with that 

 of the weathercock, indicated a moderate wind in the direction 

 of W.S.W. 



The electrometer of Peltier, interrogated at various times and 

 at intervals of 2 to 3 minutes, indicated successively —19°, 

 — 30°, —35°, —40°, —30°. A shower was observed to the 

 W.S.W., and during the last observation a small cloud which 

 crossed the zenith let fall some drops of rain. It was then about 

 10 minutes past 12 o'clock at noon, and the nimbus caused by 

 the rain to the W.S.W. approached insensibly. 



I descended to invite M. Bouvy, one of my assistants, to follow 



the indications of the galvanometer of Gourjon, while I, by means 



of Peltier's electrometer, might continue my observations on the 



summit of one of the turrets of the observatory ; my object being 



* From vol. xix. No. 7 of tlie Bulletins de I' Academic Royale de Belyique. 



