an English chemist who is often regarded as the father of chemistry. Many “firsts” are attributed to Boyle: the first modern definition of a chemical element; the first to perform controlled experiments and to publish his work with elaborate details concerning procedure, apparatus and observations; and the first to assemble what we would today call a “research group.” Boyle apparently was greatly influenced by Galileo's work. He presented what is now known as Boyle's law, which states that at a constant temperature, the density of a gas varies proportionally to its pressure. Boyle developed a key piece of apparatus - the vacuum pump- and performed numerous experiments with it, observing that pumping the air out of a container would extinguish a flame, kill small animals placed inside, and would also cause the level of a barometer to drop.