g2 ON THE ELECTRIC COLUMN. 



Two distinct But there remained a great question. These different 

 effects shown ^^^^.^^ ,^^j ^^^^^^ j^^^^ produced by the electric Jiuid only 

 uilhe pile. , . « •; 1-11-; 



when it was arrived at a great densily; while the pile pro- 

 duces the same effects with so small a quantity of the /??<?</, 

 as to be often hardly sufficient to move the gold leaf elec- 

 troscope. This has been the object of the experiments 

 contained in ray ^v^t paper, which have manifested two dis- 

 tinct effects in the pile: 1. A motion of the electric fluid 

 produced by the association of two proper metals^ independ- 

 ent of any other effect: 2. A modification of this small 

 quantity of electric fiiiid, on pervading the pile during the 

 calcination of some of its metals. A distinction first shown 

 by different dissections' of the pile, and afterward directly 

 A new instru- proved, by producing an instrument, which regains the elec' 

 meat, t,ic effects of the pile by the association of two metalsy with- 



out either its chemical effects, or the shock, 

 the electric CO- This new instrument was to be distinguished from the 

 lumn, galvanic (or voltaic) pile; therefore, in my second paper 



delivered to the Koyal Society on this subject, I named it 

 electric column, as being a spontaneous and permanent elec' 

 manifesting trie machine; and as it manifested also, by changes in its 

 fiifliience of ^ ''^^'''°*'^''/'*^'^' some variable influence of the electric state of 

 the electric the air, this new effect was to be expressed by an additional 

 state of the air. jjame. It is different from the indications of our former al- 

 mospheric electroscopes, such as elevated conductors and 

 kites, which inform us only of the comparative states of the 

 stratum of air that they attain, and of the air at the place 

 of observation ; without any indication of the changes in the 

 latter, probably connected with some phenomena, which 

 we observe, without knowing their cause.; and as the elec- 

 tric column seemed to promise a method of discovering 

 these changes, I named it also aerial electroscope. 



Such had been the principal object of my second paper 

 presented to the Royal Society; it was only in its nascent 

 state ; but as T thought it worthy to be taken up and fol- 

 lowed by other experimental philosophers, I would not 

 postpone communicating it to the public till it was more 

 advanced : it has not been published in the Phil. Trans., 

 ©bjoctof the and as 1 have since carried it farther, 1 shall here treat it in 

 pre;,e;u paper. .^ jjjff^.reut manner, dividing it into three parts; the first 



will 



