Phlogiston is Finally Put to Rest by Lavoisier
Antoine Lavoisier was a French chemist (1743-1494) who became known as “The Father of Modern Chemistry” with good reason. He named oxygen and hydrogen, predicted silicon, helped construct the metric system, and discovered that sulfur was an element rather than a compound to name a few of his achievements. In one of his more famous experiments, he burnt phosphorus and sulfur in air, and showed that the products although they weighed more than the original, the weight gained was lost from the air, thus establishing the Law of Conservation of Mass.
What about the Phlogiston theory which postulated that materials released a substance called phlogiston when they burned first described in 1667? The theory was an attempt to explain combustion and rusting and was accepted by most of the scientists of the time. However, Lavoisier demonstrated the correct role of oxygen in the rusting process as well in respiration. Along with Pierre-Simon Laplace, Lavoisier conducted experiments that showed that respiration was essentially a slow combustion of organic material using inhaled oxygen. In other words, he disproved the release of phlogiston.
At the age of 28, Lavoisier married 13-year-old Marie-Anne Pierrette Paulze who translated from English to French for him and illustrated his books. Unfortunately for Lavoisier he was essentially a tax collector for the king during the French Revolution and was tried, convicted, and guillotined on 8 May in Paris, at the age of 50.