Mermet: The King of Radiesthesia

Alexis Mermet did not coin the word radiesthesia. That credit goes to another French priest, Abbé Alexis Bouly, who put the term together in the 1920s. What Mermet built instead was the method: a documented, repeatable way of using a pendulum that earned him the nickname “the King of Radiesthesia” in his own lifetime.

His main book on that method reached French readers in the early 1930s. English readers got it in 1959, twenty-two years after he died.

Alexis Mermet was born on 12 November 1866 at Les Ollières, in the Haute-Savoie, the son and grandson of water diviners, sourciers who located wells with a forked stick before anyone called the practice radiesthesia. He was ordained a priest at Annecy on 6 July 1890 and spent the following decades moving through parishes in Savoie and then Switzerland, ending as chaplain at Jussy, in the canton of Geneva, from 1933 until his death on 7 September 1937, at 70.

Dowsing was the family trade before it became his vocation's sideline.

Mermet's public reputation is usually dated to 1913, when French-language sources place him at a dowsers' demonstration during the International Congress of Experimental Psychology in Paris, the same congress where another map-dowser, Joseph Mathieu, was tested that year. English-language sources confirm the congress and Mathieu's test; they do not independently confirm Mermet's presence there, so the claim is repeated here as reported rather than settled.

What is not in dispute is the decade that followed. By the 1920s Mermet was practicing teleradiesthesia, locating water, metal and missing objects from a map at a distance, and building the reputation that earned him his nickname.

Mermet's method depended on what he called a témoin, a sample connected to the target: a strand of hair, a piece of the metal being sought, a drop of blood on paper for a missing person. Where most dowsers worked the ground they were searching, he claimed the témoin let him work from a map instead, at any distance.

His own pendulums carried the idea further. Some were drilled hollow, a small chamber built into the body of the pendulum to hold a witness sample directly, on the theory that the material inside would shape the pendulum's response. That design, the witness-chamber pendulum, is still sold under his name.

Mermet published Le Pendule Révélateur in 1928, and his main work, most commonly dated to 1932, though later editions and secondhand catalogues also give 1933, 1934 and 1935, appeared under the title Comment j'opère pour découvrir de près ou à distance sources, métaux, corps cachés, maladies. A German translation, Der Pendel als wissenschaftliches Instrument, followed in 1935.

The English translation, Principles and Practice of Radiesthesia, made from the definitive posthumous French edition and translated by Mark Clement, was not published until 1959, by Thomas Nelson & Sons, twenty-two years after Mermet's death. For over two decades, the man some English writers were already calling the King of Radiesthesia had no book his English readers could actually read.

A public reputation is not scientific validation, and nothing in Mermet's record amounts to controlled proof that a pendulum detects anything beyond the holder's own hand movement. What his career actually documents is a milieu: French Catholic clergy, Bouly, Mermet and others, spending the interwar decades trying to turn a folk practice into something recorded and teachable. That project, not any confirmed mechanism, is what “the King of Radiesthesia” built.

Separate the claim from the discipline. Whether a pendulum detects anything is not settled by Mermet's career, however documented it was. What he left behind is a method: fix a clear question, define a witness object connected to what you're looking for, and record results consistently enough that a pattern, real or not, becomes visible. That structure is worth more than the specific claims built on top of it.