Antoine Lavoisier is deservedly considered one of the great chemists in history. We might not know of his experiments if it weren’t for his wife. She became a remarkable, if unconventional, chemist herself and had one of the weirder lives in history.
If diamonds are just lumps of precisely-structured carbon, why don't they burn? Actually, they do. And proving that they do is one of the things that cost a famous scientist his life.
There have been a few famous feuds in science history, but there's only been one that left a scientist headless. Unfortunately for all of history, in this case, the better scientist lost. That's politics for you.
Technically, it was Antoine Lavoisier that proved we have an internal combustion engine, but let's give the guinea pig credit. It nearly froze in Lavoisier's special calorimeter to prove something new about biophysics.