text: William B. Jensen notes that the earliest example of a continuous extractor is archaeological evidence for a Mesopotamian hot-water extractor for organic matter dating from approximately 3500 BC. The same mechanism is present in the Pythagorean cup. Before Soxhlet, the French chemist Anselme Payen also pioneered with continuous extraction in the 1830s.
  A Soxhlet apparatus has been proposed as an effective technique for washing mass standards.