English chemist who, for his combination of iatrochemical and alchemical traditions, is usually considered the father of chemistry. He demonstrated that chemistry is worth studying in and of itself, used rigorous experimental and quantitative methods, and gave the first modern definition of a chemical element. Boyle also tried to purify chemicals to obtain reproducible reactions. He was a vocal proponent of the mechanical philosophy proposed by Descartes to explain and quantify the physical properties and interactions of material substances. Nevertheless, he did not believe in the physical reality of atoms. He also performed numerous investigations with an air pump, and noted that the mercury fell as air was pumped out. He also observed that pumping the air out of a container would extinguish a flame and kill small animals placed inside, and well as causing the level of a barometer to drop. He presented Boyle's law, which states that pressure varies inversely as volume at constant temperature, although he was not the original discoverer. His work The Sceptical Chymist (1661) was published with the intention of ridding chemistry of meaningless verbiage. It also said that gross matter was composed of clusters of particles and that chemical changes resulted from the rearrangement of the clusters. Boyle repeated the tree experiment of Helmont, and was the first to use indicators which changed colors with acidity.

Additional biographies: MacTutor (St. Andrews)