The accomplishments of the Victorian physicists were (and are) amazing.
Among the great Victorian era scientists, I've been studying the work of James Clerk Maxwell, specifically Maxwell's equations [1] (along with the history of Victorian mathematics and physics [2]). In his short life, Maxwell made important contributions in many areas of physics. Unfortunately Maxwell died at age 48 from abdominal cancer in November of 1879 [3].
Among Maxwell's contributions are Maxwell's equations, which completed the unification of electricity and magnetism, thereby forming the concepts of electromagnetism and the electro-magnetic force. One of the really amazing aspects of Maxwell's equations is their generality. In particular, they apply to all charge and current densities, whether static or time-dependent and together they completely describe the dynamical behavior of the electromagnetic field.
Here's the best I could do with unicode to describe the differential form of Maxwell's equations (there are also integral forms of Maxwell's equations, see below):
(i). ∇·E = ρ/ε0 # Gauss's Law
(ii). ∇·B = 0 # Gauss's law for magnetism
(iii). ∇ × E = ∂B/∂t # Maxwell–Faraday equation (Faraday's law of induction)
(iv). ∇ × B = μ0 (J + ε0 ∂E/∂t)
Ampère's circuit law (with Maxwell's addition)
Maxwell's equations are important not only because they unified electricity and magnetism and completely characterized the electromagnetic field, but also because they paved the way for special relativity and quantum mechanics.