The story
Coined by the British economist John Maynard Keynes (1883–1946) in A Treatise on Money (1930; see the quotation), after the British economist Arthur Herbert Gibson, who noted the correlation in a series of articles for Bankers’ Magazine, particularly in its January 1923 and November 1926 issues (though it had previously been noted by the English economist Thomas Tooke (1774–1858)).
Etymology from Wiktionary, CC BY-SA 4.0.