Ampère return
Scientists index


André Marie Ampère

Poleymieux au Mont d'Or-Lyon 22.January.1775- Marseilles 10.June.1836



Experiment of Oersted

Ampère,  skillful mathematician,  in the September of 1820, after to have assisted to a demonstration, executed from Arago,  of the uncovered phenomenon from  Oersted  he placed mathematical the theoretical bases of electromagnetism,  perfecting them  subsequently in little months.   In 1827 published "the Memoire sur théorie   mathématique  DES  phénomènes  electrodinamiques,  uniquement déduite de the expérience".(1)
In the memories it introduces four experiments:

1)  two equal currents of opposite directions, one  near the other,  do not exercise no action on a magnetic needle;

2)   some  action  is not obtained    even if  one  of  the metallic   conductors  in the experiment is folded and bent.

3)  a conductor,  in a position to moving in the direction    of its length and      covered from one current electrical worker (   only continues)   that he enters and he exits in fixed points  of the space, is insensitive to whichever current sluice placed in its vicinities.

4) the fourth experiment    servants of three  circular currents with beams  R',   R' ',    R' ' '.    The circles,   complanari,  have their centers in   O',   O' ',   O' ''  on a straight line and    the beams  of  the circuits are such that     R'/R' ' = R' '/R' '',  and  are  also  equal  to    the relationship between the distances  O' O' ' and O' ' O' ' '.  The same current goes in hour    sense   in the external circles  and counter-clockwise in that one they centers.  In both   the conditions    the ring centers them    finds in equilibrium when the external rings are   fixed.

From these Ampère   experiments    a law derived on the interaction of the produced magnetic  fields  from  covered filiform conductors from currents,  by means of a mathematical formula  much complex that rendered account of all the phenomena  observes to you.
It demonstrated  exactly  also  that    a permanent  magnet    is behaved to the outside,  as    a cylindrical  propeller  winding covered from current electrical worker (continues), that it called "solenoid".


Note: 1) Memories on the mathematical theory of the electromagnetic, deducted phenomena only   from experimentation.