Lavoisier was known for his experimentation skills. One of his favorite experiments being turing HgO into Hg+O. He used this experiment to help himself come up with the Law of Conservation. The law states that matter cannot be made or destroyed. He also hints at the rearrangement of matter in reactions. Matter rearranged, but never disappeared.
Significance of contribution
He began the conversation on what an atom was exactly.
He was suspected of treason during the French Revolution.