.Electro-Magnetic Experiments. ?7 



pltites, one of copper and one of zinc, twisted into a splralj ant} 

 suspended in the liquid conductor. It is more moveable thaii' 

 the others, but requires to be used with pinticular caution. 



I have not as yet discovered a method of making a galvanic 

 apparatus capable of directing itself towards the poles of the 

 earth. Any apparatus for this purpose must be much more move- 

 able than any 1 have mentioned. 



Notes, hj M. Ampere, of the Commnnicat'ions ivhkh he made 

 to the Academy of Sciences. 



Sitting of September IS, !S20. 



I reduced the phenomena observed by M. Qilrstcd to two gc-^ 

 neral facts. I showed that the current which is in the pile, acts 

 on tl:c magnetic needle like that of the conjunctive wire. I de- 

 scribed the experiments by which I had established the attrac- 

 tion or repulsion of the whole of a magnetic needle, by the con- 

 junctive wire. I described the instruments whi'jh I proposed to 

 construct, and, among others, galvanic spirals. I aunoiniced that 

 the latter would produce, in all cases, the same effects as mag- 

 nets. Afterwards, I entered into some detail-s on the manner m 

 which I conceived the magnets lo act ; as only owing their pro- 

 perties to etectric currents iif planes perpendicular to their axis, 

 and u|)on the similar currents which I allow in the terrestrial 

 globe ; in short, I reduced all the magnetic phenomena to effects 

 j:iurely electric. 



Sitting of the 2,)tlv of Septeml?er. 

 I gave a further development of this theory, and I announced 

 the nevv fact, of the attraction and repulsion of two electric cur- 

 rents, without the intermediation of any magnet ; a fact whicly 

 I had observed in conductors twisted spirally. I repeated this 

 experiment in the course of the sitting. 



SirriNG of the 9th of October, 

 I presented to the Academy some experiments, which put in a 

 clear light the identity of action between the conjunctive wires 

 and the close curves, which I conceived like electric currents in 

 planes perpendicular to the line which joins the two poles of a 

 magnet. I showed on tv/o rectilinear electrical currents the same 

 effects, which I had sliown in the preceding sitting, on currents 

 in the case of conductors twisted spirally. I read at the same 

 sitting a Memoir, in which 1 gave the results of some new cx- 

 j^rimenls on the same phenomena, and on the circumstances 

 which jM-oducc them. I descril>ed llie process, which I had since 

 folio, vcd, for cakuliiting the cffccU of electrical currcntE of .i dc- 



tcimiiiatc 



