$6 Sir Humphry Davy on [Aug. 



lion of the negative and positive sides of the electrical appa- 

 ratus. 



To gain some light upon this matter, and to ascertain cor- 

 rectly the relations of the north and south poles of steel mag- 

 netized by electricity to the positive and negative state, I 

 placed short steel needles round a circle made on pasteboard, of 

 about two inches and half in diameter, bringing them near each 

 other, though not in contact, and fastening them to the paste- 

 board by thread, so that they formed the sides of a hexagon 

 inscribed within the circle. A wire was fixed in the centre of 

 this circle, so that the circle was parallel to the horizon, and an 

 electric shock was passed through the wire, its upper part being 

 •connected with the positive side of a battery, and its lower part 

 with the negative. After the shock all the wires were found 

 magnetic, and each had two poles ; the south pole being oppo- 

 site to the north pole of the wire next to it, and vice versa, ; and 

 •when the north pole of a needle was touched with a wire, and 

 that wire moved round the circle to the south pole of the same 

 needle, its motion was opposite to that of the apparent motion 

 of the sun. 



A similar experiment was tried with six needles arranged in 

 the same manner ; with only this difference, that the wire posi- 

 tively electrified was below. In this case the results were pre- 

 cisely the same, except that the poles were reversed ; and any 

 body, moved in the circle from the north to the south pole of 

 the same needle, had its direction from east to west. 



A number of needles were arranged as polygons in different 

 circles round the same piece of pasteboard, and made magnetic 

 by electricity ; and it was found that in all of them, whatever was 

 the direction of the pasteboard, whether horizontal or perpendi- 

 cular, or inclined to the horizon, and whatever was the direc- 

 tion of the wire with respect to the magnetic meridian, the same 

 law prevailed ; for instance, when the positive wire was east, 

 and a body was moved round the circle from the north to the 

 south poles of the same wire ; its motion (beginning with the 

 lower part of the circle) was from north to south, or with the 

 upper part from south to north ; and when the needles were 

 arranged round a cylinder of pasteboard so as to cross the wire, 

 and a pencil mark drawn in the direction of the poles, it formed 

 a spiral. 



It was perfectly evident from these experiments, that as many 

 polar arrangements may be formed as chords can be drawn in 

 circles surrounding the, wire ; and so far these phenomena agree 

 with your idea of revolving magnetism ; but I shall quit this 

 subject, which I hope you will yourself elucidate for the infor- 

 mation of the Society, to mention some other circumstances and 

 i'acts belonging to the inquiry. 



Supposing powerful electricity to be passed through two, 



