Lavoisier, the Father of Chemistry

Antoine Lavoisier (lah-vwah-ZHAY), 1743-1794, introduced quantitative measurement into the study of chemistry with his discovery of the law of conservation of mass. He discovered the role of oxygen in combustion and established the principles for naming chemicals. He wrote the first modern chemistry textbook in 1789.

Lavoisier performed many quantitative experiments with combustion, and concluded that the gas oxygen was being added to the substance which was burning. This required quantitative experiments in close containers in order to keep track of the mass of the gases. This was not an easy task with the tools he had at hand. Some substances formed solid oxides and thus gained mass when burning, while others produced gaseous oxides which were given off and therefore decreased in mass. The persistent work of Lavoisier established oxygen as a pure substance with particular chemical properties -- so he is often credited with discovering that pure matter consists of chemical elements.

John Dalton

John Dalton (1766-1844) proposed the basic atomic theory which forms the cornerstone of modern chemistry. Born in Eaglesfield, England in the family of a poor weaver, John was a child prodigy who started his own school at the age of 12. He became a professor at the University of Manchester in his mid twenties. He became justifiably famous for his atomic theory, but true to his Quaker convictions continued to live a very simple life.