Memories of Wolfgang Gaede on the occasion of the 100th anniversary of his birth

The development of vacuum measurements down to extremely high vacuum – XHV

“…This last improvement was mainly due to W. Gaede [15] in Germany and I. Langmuir [16] in USA with their realizations in the field of pumps (mercury rotary pump and molecular pump reaching pressure in the range of 10-5 Pa). Both the researchers (in 1915-1916) separately invented the mercury diffusion pump and in 1928 C. R. Burch invented the oil diffusion pump.…”