The Biot-Savart Law describes the magnetic field which is generated by an electric current. It related the magnetic field to the magnitude, direction, length and proximity of the electric current present. The law is used in magnetostatic approximation.

The Biot-Savart law is used for calculating the resultant magnetic field B at position r which is generated by a steady current I. A continual flow of charges is constant in time; the charge neither accumulates nor depletes at any point. The equation is:

B =(u_{0}/4π) ∫_{C}(Idl x r/|r|^3)

Maxwell considered magnetic permeability u to be a measure of the density of the vortex sea. Hence:

- Magnetic induction current

**B = uH**

Was essentially a rotational analogy to the linear electric current relationship

- Electric Convection current

**J = ρv**

Where ρ is electric charge density. B was seen as a kind of magnetic current of vortices aligned in their axial planes, with H being the circumferential velocity of the cortices.

The electric current equation can be viewed as a convective current of electric charge that involved linear motion.