Johann Friedrich Schweitzer

Johann Friedrich Schweitzer or Sweitzer, usually known as Helvetius (January 17, 1630 – August 29, 1709) was a Dutch physician and alchemical writer of German extraction.

He is known for his books Ichts aus Nichts, für alle Begierigen der Natur published in 1655, Vitulus Aureus (The Golden Calf), published in 1667 under the pseudonym Joakim Philander, and Miraculo transmutandi Metallica, Antwerp, 1667.

[2] He arrived in 1649 in the Dutch Republic, where he obtained a degree at the University of Harderwijk in 1656 with a dissertation de Peste.

He first lived in Amsterdam, but subsequently moved to The Hague,[2] where he became a physician to the Prince of Orange-Nassau (later to be William III of England).

[3] He wrote numerous books on herbs and medicine in Dutch, German, and Latin.