Toepler pump used by Ramsay, late 19th century.
© Science Museum / Science & Society Picture Library
This Toepler pump was used by Scottish chemist Sir William Ramsay (1852-1916) to remove air during his researches leading to the discovery of the rare (noble) gases of the atmosphere. In collaboration with Lord Rayleigh, Ramsay discovered argon in 1895, and this led swiftly to the discovery of helium, neon, krypton, xenon and finally radon. The discovery of these previously unknown gases added a whole new eighth column to the periodic table of the elements. For this work Ramsay and Rayleigh were awarded the Nobel prize for chemistry in 1904.