Becher's «Foolish Wisdom»

Prince Rupert and the history of malleable cast iron

Title page: Johann Joachim Becher's "Foolish Wisdom"

Johann Joachim Becher: Foolish Wisdom and Wise Folly: Or One Hundred Concepts and Propositions, Political and Physical, Mechanical and Mercantile, Some of Which Have Been Useful, Others Useless […] 1707

GF has been producing malleable cast iron fittings for over 150 years. Johann Conrad Fischer had earlier experimented with this material and was granted a patent for it in Austria in 1828. A new acquisition shows that working with malleable cast iron goes back even further in time. In 1670 Prince Rupert had his technique patented in England – a real prince!

This book – our copy is from 1707 – was written by Johann Joachim Becher, a flamboyant all-rounder. The title, somewhat unusual for today's readers, is "Foolish Wisdom and Wise Folly". The book first appeared in 1682 and was reprinted eight times. Gerhard Dünnhaupt remarks about this book: "A collection of curious ideas and inventions, plus alchemical, physical and medical experiments and formulae conceived during a stormy, 28-day sea voyage to Scotland."

Chapter 23: "Prince Rupert's invention"

Chapter 23: Prince Rupert's Invention

In Chapter 23 Becher describes "Prince Rupert's invention of casting iron pieces so that they are soft and pliable." Who was Prince Rupert (known in the German-speaking world as Rupprecht von der Pfalz)? Details can be found in Ludwig Beck's "Die Geschichte des Eisens" (The History of Iron). Prince Rupert was the son of Frederick V, Elector Palatine, and Elizabeth I of England. He was an English general and admiral, as well as "an outstanding chemist and physicist, and as such was in close contact with [Johann Joachim] Becher. [...] On 1 December 1670 he patented a process for [...] 'softening cast iron, so that it may be filed and wrought like forged iron' [...]" (p. 1274).

Back to Johann Joachim Becher's "Foolish Wisdom", where the author says about the Prince's invention: "Prince Rupert, however, […] instead of trying to harden iron into steel, made the iron soft and pliable so that it can be turned and can be made highly suitable for shooting […]. The prince has been granted a patent for this in England and is producing large amounts" (p. 34).

About the author

Johann Joachim Becher (1635-1682) taught himself the science of medicine and worked as a private physician in Mainz and later in Munich. It was here that he wrote his most important works, including his "Physica subterranea". He drew up plans for establishing a colony of the County of Hanau in South America and for developing silk manufacture. At the Imperial Court in Vienna, he was an influential advisor of Emperor Leopold I in the fields of alchemy, politics and economics. He spent the last years of his life traveling in the Netherlands and in Great Britain, where he studied British mining on the spot. Becher died in London in 1682.