246 HISTORY OF GALVANISM. 



previously and independently, as had been done in astronomy. Tl/t 

 experiments gave complex results, and the analysis of these into theii 

 ( Irmentary actions was almost an indispensable step in order to disen- 

 tangle their laws. We must, therefore, state the progress of this 

 analysis. 



CHAPTER VI. 



THEORY OF ELECTRODYNAMICAL ACTIOX. 



A MPERE'S THEORY. Nothing can show in a more striking manner 

 L*- the advanced condition of physical speculation in 1820, than the 

 reduction of the strange and complex phenomena of electromagnetism 

 to a simple and general theory as soon as they were published. In- 

 stead of a gradual establishment of laws of phenomena, and of theories 

 more and more perfect, occupying ages, as in the case of astronomy, 

 or generations, as in the instances of magnetism and electricity, a few 

 months sufficed for the whole process of generalization ; and the ex- 

 periments made at Copenhagen were announced at Paris and London, 

 almost at the same time with the skilful analysis and comprehensive 

 inductions of Ampere. 



Yet we should err if we should suppose, from the celerity with 

 which the task was executed, that it was an easy one. There were 

 required in the author of such a theory, not only those clear concep- 

 tions of the relations of space and force, which are the first condi- 

 tions of all sound theory, and a full possession of the experiments ; 

 but also a masterly command of the mathematical arms by which 

 alone the victory could be gained, and a sagacious selection of proper 

 experiments which might decide the fate of the proposed hypothesis. 



It is true, that the nature of the requisite hypothesis was not diffi- 

 cult to see in a certain vague and limited way. The conducting-wire 

 and the magnetic needle had a tendency to arrange themselves at right 

 angles to one another. This might be represented by supposing the 

 wire to be made up of transverse magnetic needles, or by supposing 

 the needle to be made up of transverse conducting-wires ; for it was 

 easy to conceive forces which should bring corresponding elements, 

 jither magnetic or voltaic, into parallel positions; and then the gene 



