James Clerk Maxwell
The life of James Clerk Maxwell - Unified Light and Electricity
Gauss's Law
Electric charge produces an electric field (Gauss's Law).
\[ \nabla \cdot \mathbf{E} = \frac{\rho}{\varepsilon_0} \]
Gauss's Law for Magnetism
There are no magnetic monopoles (Gauss's Law for Magnetism).
\[ \nabla \cdot \mathbf{B} = 0 \]
Faraday's Law of Induction
A changing magnetic field produces an electric field (Faraday's Law).
\[ \nabla \times \mathbf{E} = -\frac{\partial \mathbf{B}}{\partial t} \]
Ampère's Law with Maxwell's Addition
Electric currents and changing electric fields produce magnetic fields (Ampère-Maxwell Law).
\[ \nabla \times \mathbf{B} = \mu_0 \mathbf{J} + \mu_0 \varepsilon_0 \frac{\partial \mathbf{E}}{\partial t} \]
Sources: https://mathshistory.st-andrews.ac.uk/Biographies/Maxwell/