English chemist who, after observing that the nitrogen he obtained from air was slightly denser than that obtained from compounds, remembered and repeated Cavendish's experiment combining the nitrogen with magnesium. Like Cavendish, he found a bubble of gas left over. Using spectroscopy as introduced by Kirchhoff, he found that the lines of the gas were in new places, identifying it as a new element, which he termed argon (from a Greek word for inert). By noting that argon had a valence of zero, he postulated that a new family existed in the periodic table, and began the search for its new members. He investigated the lines of a gas obtained from a mineral, and found they corresponding to lines found in the Sun by Janssen and attributed to a new element called helium by Lockyer. Searches for other new gases in minerals proved fruitless. Ramsay then painstakingly prepared a large volume of argon, and fractionated it. He found three fractions, which he called neon ("new"), krypton ("hidden"), and xenon ("stranger"). Ramsay received the Nobel Prize in 1904 for his work on the noble gases.