Weber had already laid the foundations of the absolute system of electric and magnetic measurement, and proved that a quantity of electricity could be measured either by the force it exercises upon another static or stationary quantity of electricity, or magnetically by the force this quantity of electricity exercises upon a magnetic pole when flowing through a neighbouring conductor.
A unit magnetic pole is that which acts on an equal pole at a distance of one centimetre with a force of one dyne.
Ampere's investigations had led electricians to see that the force acting upon a magnetic pole due to a current in a neighbouring conductor was such as to tend to cause the pole to travel round the conductor.
The older operation of magnetizing a steel bar by drawing a magnetic pole along it merely consists in exposing successive portions of the bar to the action of the strong field near the pole.
We may remark, however, that although the fact of the tangential force between an electric current and a magnetic pole was clearly stated by Oersted, and clearly apprehended by A.