 The original mass of combustible material and the mass of the oxygen required for combustion equals the mass of the combustion products (ash, water, carbon dioxide, and other gases).Antoine Lavoisier, one of the pioneers in these early insights, stated that "Nothing is lost, nothing is created, everything is transformed", which would later be known as the law of conservation of mass.Lavoisier used the experimental fact that some metals gained mass when they burned to support his ideas.