Figure 3. — This wire '"bow-pattern" was the first illustration Schweigger gave of his "dou- 

 bling apparatus," though he had presented a verbal description of a single-coil arrange- 

 ment somewhat earlier. The purpose of the bow pattern was to show that compass needles 

 at the centers of the two loops deflected in opposite directions. (From Journal fur Clumie 



tm>/ Physik ) 



PAPER READ IN HALLE, NOVEMBER 4, 182.O 



[The first half of this paper describes successful 

 observations of the reaction-force of a magnetic 

 needle on the connecting wire of a voltaic circuit, 

 achieved by pivoting the connecting wire in the 

 form of brass needles above and below the compass 

 needle. Though the multiplier configuration of 

 needle and wire is in fact present here, Schweigger 

 does not mention it, evidently regarding this as a 

 separate project. He continues.] 



In my lecture of September 1 6th, I showed that Oer- 

 sted's results depend, not on the voltaic cell, but only 

 on the connecting circuit. The principle I have used 

 for amplification of the effects, for the construction of 

 an electromagnetic battery as it were, was the winding 

 of wire around the compass, and I now present to the 

 Societ) .1 bow-pattern of multiple-wound, wax-insulated 

 wire Figure 3." [There wen- no illustrations with 

 Schweigger's firsl paper.] "While a single wire, using 

 iIm weak electric circuit here, deflects the magnetic- 

 needle only 30 or 40 , if the compass is placed in one 

 of the openings of this pattern, the needle is deflected 

 go° to the east. 01 in the other opening go° to the west, 

 using the same weak electric circuit .... 



The "bow-pattern" device has novelty interest 



only, adding nothing to the elucidation of the multi- 

 plier phenomenon. The same is true of Schweigger's 

 next proposal, shown in figure 4. "... I will now 

 add another apparatus, which is just ,111 extension of 



the previous one, whereby the needle can take up 

 any angle from 0° to 180°." A short length of circular 

 glass tubing, of inside diameter large enough to 

 contain a compass needle, stands with its axis vertical 

 and has single or multiple loops of wire wound on 

 it in vertical diametral planes. In the illustration, 

 successive plane coils ate inclined at 30° to one 

 another. ". . . the electric current flows through the 

 whole wire, and the needle moves under all of these 

 currents, and coming always into another loop can 

 take any desired angle." 



With much further theorizing about "the correla- 

 tion of magnetism with the cohesion of bodies," 

 Schweigger states again his evaluation of his dis- 

 covery: "Oersted succeeded in electromagnetic re- 

 search by using a spark-producing cell, which could 

 make a wire glow. My amplifying electromagnetic 

 device needs only a weak circuit of copper, zinc, 

 and ammonium chloride solution." 24 



24 The German work Kette has been translated as "circuit" 

 throughout. Although the equivalence of these words is clear, 

 for example, in Ohm's work of 1826, the context in which 

 h:l!, iv sometimes used in 1820 and 1821 indicates that the 

 concept of a "circuit," in the sense of the wiring external to 

 the source of electricity, has not been established, flu- wiring 

 is regarded nunc- as something incidental, used to "close" 

 the cell, the < ell being considered essentially the whole of the 

 apparatus. This view underlies the many attempts to correlate 



Hi' 1 >ersted phenc -n,i with cell materials and design, and 



with the use of such terms as "chemical magnetism" by Eriuan 

 and others. 



130 



1,1 III II\ 240: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



