On High Vacuum and Low Temperatures

The transition to quantum physics during the early years of the 20th century was preceded during the last two decades of the 19th century by a subtle revolution in the types of experiments undertaken in many physical laboratories. Starting around 1880, experiments were initiated to determine the magnitudes of atomic/molecular parameters by direct manipulation of particles generated by fragmentation of numerous gaseous compounds. This could be successfully undertaken when sufficiently low pressures of ambient gases were attained. In turn that depended on the development of efficient vacuum pumps and cryogenic liquids.