19. Kalium (Potassium) - Elementymology & Elements Multidict

Potash (Neolatin potassa, Potassium carbonate, K₂CO₃) was obtained from the ashes of plant material. The ashes was leached and the solution was evaporated to dryness, an operation at one time carried out in iron pots: hence the name from "pot" and "ashes." The English term appears for the first time in 1648, and is a loan-translation of Dutch potaschen.
From antiquity to the Middle Ages no difference was made between potash and soda (Sodium carbonate, Na₂CO₃), both were named by the Arabs Alkali. This word was derived from قِلْو qalay, "to fry or roast in a pan". Al-qali is "the substance that had been roasted" or "ashes of the plant saltwort. In Europe, both substances were named natron.

Martin Heinrich Klaproth, in his paper for the Royal Academy of Berlin of 26 January 1797, was the first to distinguish the both alkalis: he suggested the name kali for vegetable alkali and natron for mineral alkali (see Sodium / Natrium.)

Gay-Lussac and Thénard, who too investigated the alkalis, named the metals initially métal de potasse and métal de soude, and later also Potassium and Sodium.

The results of Davy's research were made public in German by Ludwig Wilhelm Gilbert in his Annalen der Physik of 1809 (vol. 31). Many articles were translated by Gilbert himself, he calls his work a "free translation" since he added his own comments. I have not seen Gilbert's translation of Davy's article yet, since vol. 31 (vol. 1 of the new series) is not available in the Bibliotheca Gallica. However, a note in a translation of a later article by Davy (note) makes clear what Gilbert's idea of a translation was:

Translation: The reader will remember from these Annalen that Davy named these bodies Potassium, which I replaced by Kalium, just as Davy's name for the Natron-Metal, Sodium, is represented by Natronium, in agreement with the German nomenclature. These names I will use throughout this article.

Gilbert obviously followed the 1797 proposal by Klaproth.
In 1808 Gehlen suggested Kalin(um) and Natrin or Natrinmetall.

In 1813 Berzelius published in a British journal, Thomas Thomson's Annals of Philosophy, his system of atomic symbols as one- or two-letter abbreviations of Latin names for the elements. In this first paper he followed the British discoverer Davy nomenclature and abbreviated Potassium and Sodium as Po and So. But within a year Berzelius decided in favor of Kalium and Natrium.

Despite this, as the list of names in different languages to the left shows, the English and French speaking countries followed Davy and Gay-Lussac/Thénard with Sodium and Potassium, and the Germanic countries adopted Gilbert/Klaproth's names Natrium and Kalium.

Statue of Sir Humphry Davy in his birth place, Penzance, Cornwall, England.
Photo by Peter van der Krogt, 20 July 2004.

Sir Humphry Davy
The most famous son of Penzance was one of the leading scientists of the 19th century - Sir Humphry Davy.
Davy was born in Penzance in 1778 the son of a woodcarver. At the age of 16 he was apprenticed to a local doctor and became interested in chemistry. In 1798 he left to work in a medical laboratory in Bristol. There he discovered the pain relieving effects of laughing gas (nitrous oxide) and suggested its anaesthetic use.
By the age of 24 Davy was a professor of chemistry at the Royal Institution. He founded the science of electro-chemistry and discovered six new elements including potassium and sodium [and boron, magnesium, calcium, and barium]. He became famous and was honoured throughout Europe.
Davy is remembered now for his work on the miners safety lamp which bears his name, but perhaps his greatest contribution to science was the encouragement he gave to the young Michael Faraday.
Davy kept in touch with his roots and supported the Royal Geological Society in Penzance and left money to his old school. He died in 1829.
This statue was erected in 1872 and was produced by the sculptors Wills of London and is of white marble.

ITYAN
POTASSIUM, the Plant's tonic metal,
Call'd Kalium, of silver-white colour;
Oxides when exposed to dry Air, producing
Potassium Monoxide; thrown in water
It instantly fires ! forming the Hydroxide.
It can be viewed only through clear liquids
Which do not contain its friend Oxygen:
It cuts soft with knife at common temp'ratures.