EULOGY ON ARTHUR AUGUSTE DE LA RIVE. 189 



and noble families of the country, and tlie taste for letters and science 

 it promoted, with the habit of devotion to their culture, was transmitted 

 from generation to generation, enabling the school of Geneva to main- 

 tain a high position among the most renowned universities of Europe. 

 It was a source of intellectual activity, and a center of light, such as 

 is supported only by great effort in countries of much larger extent than 

 Switzerland. 



As soon as the discovery of Oersted was announced, Ampere offered 

 the following explanation : The frictional electricity, or that developed 

 by rubbing glass, long known, is a fluid in repose, and constitutes stat- 

 ical electricity. The electricity of the voltaic pile is this same fluid iu 

 motion in the direction of the axis of the conductors, and this is dynam- 

 ical electricity. Again, this same fluid circulating around the molecules 

 of a bar of iron or steel, in a plane perpendicular to the axis which 

 united the two extremities, is magnetism. To give a material illustration 

 of these forces, the water which moistens the surface of a solid body 

 may represent statical electricity, the water which flows through an 

 aqueduct dynamical electricity, and that which passes in the turns of 

 an xVrchimedian screw, magnetism. 



On the 4th of September, 1820, Arago announced to the French 

 Academy the facts whose confirmation he had witnessed at Geneva, 

 and on the 25th of the same month Ampere read his valuable memoir, 

 which alone would have given his name one of the highest places iu the 

 history of science. His theory of the principles of electro-magnetism 

 was founded upon his fundamental experiment that two voltaic currents 

 in the same direction attract each other, and, on the contrary, repel each 

 other when they are iu opposite directions — a phenomenon he had fore- 

 seen and predicted as a result of his a priori conception. To this strik 

 ing proof of the truth of his theory he soon added another. He imitated 

 a magnet by passing a voltaic current through a metal wire coiled into 

 '1 spiral, and suspended freely in a vertical plane. This spiral was 

 affected by the action of the earth like the magnetic needle, which 

 Ampere explained by supposing that the lower parts of the wire, that 

 is, those nearest the earth, controlled the whole. This experiment was 

 also exhibited in its simplest form by suspending a rectangular wire so 

 that it could move freely. When a voltaic current was passed through 

 this, it arranged itself at right angles to the direction of the magnetic 

 needle. Now Gaspard De La Rive removed the lower horizontal part, 

 and the remainder of the wire was as much affected by the terrestrial 

 influence as when the rectangle was complete. 



The explanation of Ampere was thus shown to be incorrect, and his 

 theory for a time lost its best support. His state of mind under the 

 influence of this disappointment bordered on derangement. When alone, 

 he passed hour after hour in j)rofound meditation ; and when with his 

 family-, pursued the avocations of life in a sort of somnambulism, obliv- 

 ious of everything around him. At length, however, in a moment of 



