The coiner of the term "oxygen"
He played a major role in his country's adoption of the metric system.  His wife Marie-Anne translated his scientific works into English for him while he worked as a gunpowder administrator.  The coiner of the term "oxygen", he also worked as a tax collector prior to his debunking of the phlogiston theory.  The empirically-derived law of conservation of mass is often known as his law, and he wrote the first general textbook on chemistry in 1789.  FTP, name this "father of chemistry" who was guillotined during the French Revolution.
He played a major role in his country's adoption of the metric system.  
Antoine-Laurent Lavoisier