We can scarcely believe that Amp�re really discovered the law of action by means of the experiments which he describes. We are led to suspect, what, indeed, he tells us himself, that he discovered the law by some process which he has not shown us, and that when he had afterwards built up a perfect demonstration he removed all traces of the scaffolding by which he had raised it.

While riding in a carriage to a meeting at the Academy in Paris, Ampere was struck by a brilliant notion which he immediately jotted down: dH=ipdl/r^2 (in which p is the perpendicular distance from P to the line of the element dl; or DH = i sin 0 dl/r2). Upon his arrival, Ampere paid the driver, ran into the building to share his discovery, and promptly realized that he had written his notes on the inside of the carriage itself. After an extensive search of the streets of Paris, Ampere's runaway equation was found.