Martine de Bertereau (c. 1590 – after 1642), also known as Baroness de Beausoleil, was a French mineralogist who was the first recorded female mineralogist and mining engineer. She and her husband, Jean de Chastelet, traveled extensively throughout Europe in search of mineral deposits and fresh ground water under the employment of various nobles and royals. During one such mining expedition, which saw Martine and Jean surveying potential mine sites in France for Louis XIII, the family were accused of witchcraft and forced to flee to Hungary. Later, Martine, Jean, and their oldest daughter were arrested, and eventually died in prison sometime after 1642. During her lifetime, Martine produced multiple pieces of literature derived largely from the Roman engineer Vitruvius's De architectura. While her success came from a thorough understanding of geology, Martine was not forthcoming in her writings about her actual methods. Instead, she promoted the idea that she was using magic or then-accepted pseudo-scientific ideas such as divining rods. It is not known for certain why Matine lied about her actual methods, but it may have been to prevent others from capitalizing on her seemingly-unbelievable success, as well as to boost her own reputation among potential clients. Nonetheless, her literature provides a unique glimpse into the craft and skills required to mine in the 17th Century.
Life Martine de Bertereau was born c. 1590 and came from a noble French mining family in Touraine. Her father, Pierre de Bertereau, was a chevalier and seigneur de Montigny. In 1610, she married Jean de Chastelet, Baron de Beausoleil et d'Auffenbach, a mining expert who had been named commissioner general of mines in Hungary by Holy Roman Emperor Rudolph II They had multiple children. Their eldest daughter, who died in prison with her mother, and their eldest son, Hercule, are the only two whose lives have been recorded. From 1610 until 1626, they spent much of their time travelling in search of mineral deposits. During this time, they are believed to have crossed the Atlantic to Potosi, Bolivia, to visit mines. In 1626, Martine and Jean were summoned back to France to begin work on restoring the French mining industry. In 1627, their son, Hercule, fell ill of "flaming heat in the intestines", and spent a few weeks recovering in Chateau-Thierry. During this time, Martine discovered a natural spring nearby and claimed it had healing powers, informing the local doctor of her find. The town subsequently became an attraction in which the ailed and wealthy visited. Today, geological historian Martina Kölbl-Ebert has proven this to be a long-lived form of scientific fraud. Later that year, while at their mining base in Morlaix, Brittany, the local clergy took the claims of mystical abilities seriously, and accused Martine and her husband of witchcraft. No charges were made, but the couple were forced to leave France and fled to Germany, and then Hungary. After being unable to recoup their losses, they returned to France.
In 1632, Martine wrote to King Louis XIII in hopes of receiving permission to excavate the mines she and Jean had found before fleeing. In her letter, she proposed a business model in which they could find more precious materials using questionable methods such as divining rods, things that neither she and her husband actually employed. Nonetheless, once these dubious methods are removed from her proposal, the document details a reasonably sound methodology for detecting mineral deposits. In 1640, after no response from the King and feeling that she and Jean had not been paid for their work, Martine wrote to the king's secretary, Cardinal Richelieu, and again did not receive a response. Two years after her letter to Richelieu, she was arrested, along with her husband and eldest daughter, on the charges of palm reading, horoscopy, and astrology. Martine and her daughter were imprisoned at the Château de Vincennes, while the Baron was sent to the Bastille. All three died in prison sometime after 1642.
Works The baroness wrote two reports on her work with her husband. The first, titled Véritable déclaration de la découverte des mines et minières was sent to Louis XIII in 1632 and listed 150 French mines the couple had discovered. The first article also describes mineral deposits in France, as well as the somewhat ‘esoteric’ use of dowsing rods to locate water. This document also contains many practical and scientific considerations that allow us to understand the state-of-the-art hydrogeology of the 17th Century. The second was in the form of poetry, addressed to Cardinal de Richelieu La restitution de pluton (1640), which in reality is a plea for the couple, more specifically for Martine, to be paid for the work they undertook for the king. In it she seeks to defend her unusual position as a woman in the mining industry.
"But how about what is said by others about a woman who undertakes to dig holes in and pierce mountains: this is too bold, and surpasses the forces and industry of this sex, and perhaps, there is more empty words and vanity in such promises (vices for which flighty persons are often remarked) than the appearance of truth. I would refer this disbeliever, and all those who arm themselves with such and other like arguments, to profane histories, where they will find that, in the past, there have been women who were not only bellicose and skilled in arms, but even more, expert in arts and speculative sciences, professed so much by the Greeks as by the Romans.”
References
Bibliography Wonderful history in modern times, Louis Figuier, Hachette, Paris, 1860 The Veterans mineralogists of the kingdom of France, Nicolas Godet, Ruault, Paris, 1779 Biography universal ancient and modern, Michaud, Paris, 1843
