Atmofpheric 

 elc&ricity. 



286 EXAMINATION 0!* VOLTa's EXPERIMENTS, &C. 



purpofe ; then join the two inftruments as in fig. 4. While the 

 eflfervefcence is going on, turn back the moveable plate of the 

 large condenfer into the polition of the doited line, fig. 2, 

 taking care not to touch the fixed plate; then if the excited 

 electricity be very ftrong, the gold leaf will diverge ; but if not, 

 juft move the electrometer fo that it is quite free from the pin, 

 turn back its moveable plate, and if a fufftcient quantity of 

 electric fluid be excited, the gold leaf will diverge. 



To Jhew if there be any fenfible Quantity of Ekclric Fluid in the 

 Atmqfphere. 



Screw the flick m into e of the large condenfer ; a conveni- 

 ent place being chofen not much furrounded by buildings or 

 trees, let the inftruments combined as in the laft experiment, 

 and proceed in the fame manner. 



Method of applying the combined Condenfers to the Galvanic 

 Instrument. 



Screw the fhort end of no into e of the large condenfing 

 plate (the inftruments being combined as in the former experi- 

 ments) ; bend the end downwards, at fuch a diftance from the 

 table, or whatever it may ftand upon, that the two pieces of 

 metal, zinc and copper, as at n, can be put under it, and drawn 

 away from under it again, without its touching the table when 

 the metal is drawn away. Take two pieces of metal, zinc 

 and copper, about the fize of half a crown or upwards, either 

 feparate or foldered together, with their flat fides in contact, 

 and puih them under the end n of o n. After remaining a thort 

 fpace of time, a quarter or half a minute, draw them away from 

 under the point, and take notice that the point does not touch 

 the table, or any other conductor ; then turn back the moveable 

 plate of the large condenfer ; move the electrometer fo that its 

 plate (hall no longer touch the pin of the large plate, and then 

 turn its moveable plate back; the gold leaf will remain undis- 

 turbed. 

 Elearicity from Turn up the condenfing plates to their flrft pofition ; place- 

 the galvanifmof the two inftruments together as before, taking particular care 



platM. 6 Par ° f that tne fixed P late of tne eIe ^ rometer condenfer touches the 

 pin proceeding from the large plate. Lay upon the pieces of 

 metal before ufed, a piece of woollen cloth well foaked in a fo- 

 lution of muriate of ammonia, or any other menftruum com- 

 monly 



Method of ap- 

 plying the con- 

 denfer to the gal 

 vanic inftru- 

 ment. 



plates. 



