Robert Boyle, the great English chemist, is often regarded as the "founder of modern chemistry" because he was a firm believer in experiment rather than theory. Throughout his lifetime, Boyle insisted that chemistry was farm more than a mere subdivision of medical knowledge. Indeed, the results of his brilliant work proved that chemistry was itself a full-fledged science.Boyle's best-known achievement is the Law that bears his name today-Boyle's Law, which states the relation between the pressure and volume of gases. He was also the first to perform the bell-in-vacuum experiment with an efficient air pump, proving that air is the normal medium by which sound reaches our ears.Among Boyle's other accomplishments were the perfection of the thermometer into a sealed unit, and the development of the barometer in the form it is used today.