ON THE ELECTRIC COLUMN. 259 



the operations which we observe in the atmosphere, it is not 

 to be neglected ; for we cannot arrive at any distant object, 

 but by successive steps. 



This is the consideration, that has induced me to fix my Hence attenti- 

 attention on the electric phenomena manifested by the in- "q ,j^°e ^^gj^al 

 strument, which I have described under the name of ama/ electroscope. 

 electroscope: as from the above atmospheric phenomena 

 concerning lightning and thunder, which cannot leave any 

 doubt, that they are produced by a certain decomposition of 

 the atmospheric air; and from the correspondent circum- 

 stance of a formation of new electric Jl aid in the atmosphere, 

 during the period of the day, when, the greatest part of the 

 aqueous vapour vanishing in it, there remains scarcely any 

 ponderable fluid but atmospheric air; it is manifest, that the 

 electric Jluid is one of the substanc€;s most intimately con- 

 cerned in the chemical processes, which take place in the 

 atmosphere, and on the nature of which it is the most im- 

 portant to acquire more knowledge. 



It may be seen in the tables of my observations of this Its movement? 

 new instrument, thai the changes in the frequency of the """f ""^" 

 strikhigs of the little pendulum have no determined con- mo2«tur«« 

 nexion with those of either heat or moisture in the room ; for 

 though /ifaf commonly increases in the course of each day, at 

 the same time as the frequency of the strikings, nevertheless 

 the former is not the cause of the latter ; since with the same 

 degrees of heat the frequency of the strikings is very diffe- 

 rent on ditierent days. With respect to the correspondence 

 of this phenomenon with the variations of the barometer, 

 my observations have been too short for deciding any thing 

 on this object, though I felt much interested in it ; and 

 beside=i, the barometer had but small variations during this 

 short time, being alvvays rather high. Therefore, this is a. 

 course of correspondent observations which remains to be 

 followed. 



The observations contained in the last table create a new Variations in 



interest in this pursuit, as they mav become a mean of dis- f']^ '^^'^cirtcttt- 



, . ' of the ground 



covering the changes in the comparative electric states of the ami air. 



ground and the air near it.- The htt]e pendulum, by its 



silver wire, being placed in connection with the zinc side in 



these experiments,. was thei;efore/jo.?i/ii;e ; and in this case 



P 2 («<c 



