Mr. Tatuni on Elect ro-Magnelism. 243 



pendicular poles, making eight poles on one side of the equa- 

 tor of the needle, which may be represented by N N S S and 

 nn s s, fig. 1 1 . 



And as similar effects are produced on the opposite side of 

 the equator of the needle (but with this difference, that attrac- 

 tion is produced instead of repulsion, and vice versa), the 

 needle must possess at least sixteen poles. 



But if the results of the experiments related at the com- 

 mencement of this paper be not borne in mind, it might be 

 thought that these attractions and repulsions resulted from 

 dissimilar poles on opposite sides of the connecting wire : — but 

 this I think I have proved is not tne case. 



Perhaps these phsenomena may be further illustrated by 

 R A a r, fig. 9, which may represent the two edges of a mag- 

 netic needle with its transverse poles, in which R on the lel't 

 hand may represent a north pole, and A on the right hand 

 a south pole : and also a on the left a south pole, and r on 

 the right a north pole. But I do not consider that the mag- 

 netic fluid circulates in straight lines in a transverse dii'ection, 

 as from R to A, or in a perpendicular direction, as from R 

 to a; but that it circulates in a spiral direction, makhig one 

 complete revolution, as from A 1 to R in the upj^er part of 

 fig. 10; the letters of which figure will represent the eight 

 transverse and perpendicular poles ; and the several spiral 

 lines, the direction of the fluid from and to the four opposite 

 poles; and the lower part of the same figure may represent 

 the opposite end of the needle, where the spirals indicate the 

 fluid as circulating in an opposite direction. 



This spiral direction of the fluid will, I consider, account 

 for the motion of that excellent little rotatory cylindrical ap- 

 paratus of M. Ampere, which it is well known rotates in an 

 opposite direction when placed on a dissimilar pole of the 

 magnet. It will also, in my opinion, account for the advancing 

 motion of the closed helix of M. de la Rive up the magnet, 

 as well as the rotation of a magnet roimd a wire, and a wire 

 round a magnet, invented by Mr. Faraday. 



And as I consider that the fluid from the copper side of the 

 Voltaic apparatus circulates in an opposite spiral direction 

 to what it does when passing from the zinc side, I thought 

 that if I varied M. Ampere's apparatus, by substituting zinc in 

 the place of his double cylinder of copper, and coji[)cr in the 

 place of his single cylinder of zinc, it would produce a con- 

 trary rotation ; — which fully answered my cxjiectation. 



There also appears a coincidence in the spiral direction ol" 

 the fluid, and the helixes when forming part of (heVoltaic 

 circuit: for when pieces of steel arc placed in a left-handed 



II h 2 hdix 



