  It is well known in classical electrodynamics that the magnetic field given
by a current loop and the electric field caused by the corresponding dipoles in
sheets are very similar, as far as we are far away from the loop, which enables
us to deduce Ampere's magnetic circuital law from the Biot-Savart law easily.
The principal objective in this paper is to show that synthetic differential
geometry, in which nilpotent infinitesimals are in abundance, furnishes out a
natural framework for the exquisite formulation and its demonstration. This
similitude in heaven enables us to transit from the Biot-Savart law to Ampere's
magnetic circuital law like a shot on earth.
