370 Modification of Ampere's Rotating Galvanic Element. 



Art. XIL — Modification of Ampere's Rotating Galvanic Ele 



ment; by T. Edmondson, 3VL D. Baltimore. 



The instrument is constructed in such a manner, that, the current 

 of galvanism proceeding from the zinc side of the small element, 

 will pass through a helix arranged as an electro-magnet, as it circu- 

 lates onward to the copper side of the element. 



a, the zinc cylinder in 

 section, — b, the double cop- 



, the electro- 



coated copper 

 a tube of the 



per cell, 



magnet, made, simply by 

 wrapping a 

 wire around 

 common tinned iron, — </, a 

 small metallic cup contain- 

 ing a globule of quicksilver, 

 into which is dipped one 

 end of the helix, — e, a small 

 agate center, intended for a 

 non-conductor, — f a metal- 

 lic 



cup 



also containing a 

 globule of quicksilver, into 

 which is dipped the other 

 end of the helix. 



Upon exciting this small 

 element with an acid solu- 

 tion, the current of galvan- 

 ism prevented from passing 

 directly from the zinc to the 

 copper, on account of the 

 non-conductor at e, is obli- 

 ged to traverse^ and circu- 

 late through the helix to d, 

 before it can reach the cop- 

 per side of the galvanic ar- 

 rangement. 



The instrument has fre- 

 quently revolved two hun- 

 dred times in a minute, the 

 copper cell moving fast in 

 one direction, and the zinc 

 cylinder in the opposite di- 

 rection with great rapidtiy. 



