text: In the English speaking world, the term "clarke" was not even used in Wells(1937) which introduced Fersmans proposal, nor in later USGS articles such as Fleischer(1953). They used the term "relative abundance of the elements". Brian Mason also mentioned the term "clarke" in Mason(1952)(mistakenly attributing it to Vladimir Vernadsky, later corrected to Fersman in Mason(1958)), but the definition slightly differed from Fersmans, limiting it only to the average percentage in Earth's crust, but allowed to exclude hydrosphere and atmosphere. Besides for explaining the term, Mason himself did not use the term "clarke".
  A variant term "clarke value" is occasionally used (examples:). However, "clarke value" can have a different meaning, the clarke of concentration (example:).
  Terms "clarke number" and "Clarke number" are found in articles written by Japanese authors (example:).