AMPERE 225 



He retained a childlike disposition up to his old age, but 

 apparently he was not without a great deal of self-will. He 

 was often tortured by doubt in small matters as well as 

 great ones, and at times, after the death of his first wife, suf- 

 fered domestic misfortune, so that life, in spite of all the 

 recognition that it brought him, was by no means always 

 satisfactory, a fact expressed in the epitaph chosen by him- 

 self: tandem felix (Happy at last).i 



Ampere's successes in electro-dynamics depend before all 

 upon his clear grasp of the essential features of these phe- 

 nomena, first opened up by Oersted, and presenting in the 

 beginning a highly complicated and confusing picture, and 

 upon his own observation. His further progress was due to 

 skilful experiment based on questions stated with insight. ^ 



Simply to grasp what happens in the connecting wire of a 

 voltaic pile was then a difficult matter, and required a firm 

 hold to be kept on the essential points of observation. 

 Ampere succeeded excellently in this, and settled the idea of 

 the electric current, at that time undefined, in a manner 

 which has been of the greatest advantage to progress. Volta, 

 it is true, had made use of the term electric current,^ and 

 people were also accustomed since Gray's time to speak of 

 the conduction and flow of electricity. However, when we 

 recollect that on the discharge of the pile, and likewise of a 

 Leyden jar, both electricities were supposed to flow in oppo- 

 site directions on account of their attraction for one another, 



1 See a collection of letters and recollections, which however does not 

 afford very much information, Andre Marie Ampere etJ.J. Ampere, by an 

 anonymous authoress, Paris, 1875. One thing at least is clear that 

 Ampere's doubts, which often tortured him, related to a considerable ex- 

 tent to the dogmas of the Catholic church, of which he was a member, as 

 was his first wife. 



2 Ampere's publications in the period directly after Oersted's dis- 

 covery were reprinted in Paris in 1921 under the title Memoir es sur I'^lec- 

 tromagnetisme et V ^lectrodynamique. 



3 In Volta's original French manuscript, published in the Philosophical 

 Transactions, vol. 83, 1793, we already have in the first corresponding con- 

 nection the words 'courant ^lectrique.' 



Qs 



