Complex sentence: In 1854 he began work as an assistant lecturer in physics at the Conservatory of Arts and Crafts in Paris, and in 1860, rose to the post of Professor of Physics at the Polytechnic Association for the Development of Popular Instruction.
Split into simpler sentences: In 1854 he began work as an assistant lecturer in physics at the Conservatory of Arts and Crafts in Paris. In 1860 he was promoted to the post of Professor of Physics at the Polytechnic Association for the Development of Popular Instruction.