Marie Crous
Encyclopedia
Marie Crous was a French mathematician. She introduced the decimal system to France in the 17th century.
. She was published by 1636, and by 1641 she published a study on the decimal system
, which she dedicated to "the saffron-tinted princess" Madame de Combalet, Duchesse d'Aiguillon
, niece of Cardinal de Richelieu and a well known patron; she was a friend of Marin Mersenne
. However, Marie Crous would never be cited by the eminent members of the academics and scientists within the Minim
Roman Catholic religious order, who dominated scientific research in France during that period, and she was never acknowledged as a woman of learning.
, goes well beyond what was provided at the time in calculation manuals. She wrote, Her work introduced two fundamental innovations: the decimal point (today called the virgule in French) to separate the mantissa
of the decimal parts, as well as the use of a zero in the decimal part to indicate that a place is absent. In doing this, she gave form to current decimal numbers. She named the zeroes nuls as the German were doing.
Talented in writing as well as mathematics, she developed among other things the method of Pestalozzi
and what she called denominational division, which has great utility for mental calculations, notably in its application in the rule of three
.
Crous' work (the first edition dates to 1635-1636) begins with an epistle to her noble patron. She expresses gratitude for her help in these terms : Nevertheless, she does not attribute the merit of her inventions to her. In the Preface of her Abrégé recherche (Research Abstract), Marie Crous assures that she made her work
units of measurement, such as the toise, with measurements in tenths as a more efficient system:
From this perspective, Marie Crous provided a basis for the metric system
decimal.
Mathematician Olry Terquem
regretted that her name has not yet been given to a street in Paris. More recently, Catherine Goldstein devoted part of her artcile, "Neither public nor private: mathematics in early modern France" to Crous.
, publié par T. Bachelier, article sur Marie Crous p. 200 et seq. Ou Nouvelles annales de mathématiques, Volume 14 p. 200 et seq (1852). Georges Maupin, Opinions et curiosités touchant la mathématique (deuxième série) d'après les ouvrages français des XVIe, XVIIe et XVIIIe siècle, édité à Paris chez Naud (1898). pp. 230–243.
Biography
Coming from a modest origin, Marie Crous became an accomplished writer and teacher at Charlotte-Rose de Caumont La ForceCharlotte-Rose de Caumont La Force
Charlotte-Rose de Caumont de La Force or Mademoiselle de La Force was a French novelist and poet. Her best-known work was her 1698 fairy tale Persinette which was adapted by the Brothers Grimm as the story Rapunzel....
. She was published by 1636, and by 1641 she published a study on the decimal system
Decimal system
Decimal system may refer to:* The decimal number system, used in mathematics for writing numbers and performing arithmetic.* The Dewey Decimal System, a subject classification system used in libraries....
, which she dedicated to "the saffron-tinted princess" Madame de Combalet, Duchesse d'Aiguillon
Duchesse d'Aiguillon
Marie Madeleine de Vignerot du Pont de Courlay, Duchesse d'Aiguillon was the daughter of Cardinal Richelieu's sister, Françoise du Plessis and her husband René Vignerot....
, niece of Cardinal de Richelieu and a well known patron; she was a friend of Marin Mersenne
Marin Mersenne
Marin Mersenne, Marin Mersennus or le Père Mersenne was a French theologian, philosopher, mathematician and music theorist, often referred to as the "father of acoustics"...
. However, Marie Crous would never be cited by the eminent members of the academics and scientists within the Minim
Minim
Minim may refer to:* Minim , a note length, another name for a half note * MINIM , an industrial rock band from Spain* Minim , an amount of fluid...
Roman Catholic religious order, who dominated scientific research in France during that period, and she was never acknowledged as a woman of learning.
A seminal publication
Her work, printed by Simon StevinSimon Stevin
Simon Stevin was a Flemish mathematician and military engineer. He was active in a great many areas of science and engineering, both theoretical and practical...
, goes well beyond what was provided at the time in calculation manuals. She wrote, Her work introduced two fundamental innovations: the decimal point (today called the virgule in French) to separate the mantissa
Mantissa
* The mantissa is the significand in a common logarithm or floating-point number.* Metaphorically, it is the part of the self that eludes conscious awareness or self-understanding.* An addition of little importance.Mantissa may also refer to:...
of the decimal parts, as well as the use of a zero in the decimal part to indicate that a place is absent. In doing this, she gave form to current decimal numbers. She named the zeroes nuls as the German were doing.
Talented in writing as well as mathematics, she developed among other things the method of Pestalozzi
Pestalozzi
Pestalozzi may refer to:* Johann Heinrich Pestalozzi * Hans A. Pestalozzi Schools with that name:* Colegio Pestalozzi, Argentina* Pestalozzi-Gymnasium Biberach, Germany* Kinderdorf Pestalozzi, Switzerland...
and what she called denominational division, which has great utility for mental calculations, notably in its application in the rule of three
Rule of Three
Rule of three may refer to:*Rule of three , for calculating a confidence limit when no events have been observed*Rule of Three , a tenet of Wicca*Rule of three , a computation method in mathematics...
.
An independent spirit
A visionary
In her Preface to Charlotte de Caumont, she referred to trades workers in construction in Paris, who were at that time beginning to replace pre-Metric systemMetric system
The metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...
units of measurement, such as the toise, with measurements in tenths as a more efficient system:
From this perspective, Marie Crous provided a basis for the metric system
Metric system
The metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...
decimal.
Mathematician Olry Terquem
Olry Terquem
Olry Terquem was a French mathematician, best known for his work in geometry, where he proved Feuerbach's theorem about the nine-point circle of a triangle...
regretted that her name has not yet been given to a street in Paris. More recently, Catherine Goldstein devoted part of her artcile, "Neither public nor private: mathematics in early modern France" to Crous.
See also
- 0 (number)0 (number)0 is both a numberand the numerical digit used to represent that number in numerals.It fulfills a central role in mathematics as the additive identity of the integers, real numbers, and many other algebraic structures. As a digit, 0 is used as a placeholder in place value systems...
- Decimal systemDecimal systemDecimal system may refer to:* The decimal number system, used in mathematics for writing numbers and performing arithmetic.* The Dewey Decimal System, a subject classification system used in libraries....
- MantissaMantissa* The mantissa is the significand in a common logarithm or floating-point number.* Metaphorically, it is the part of the self that eludes conscious awareness or self-understanding.* An addition of little importance.Mantissa may also refer to:...
- SignificandSignificandThe significand is part of a floating-point number, consisting of its significant digits. Depending on the interpretation of the exponent, the significand may represent an integer or a fraction.-Examples:...
- Rule of three (mathematics)
- PestalozziPestalozziPestalozzi may refer to:* Johann Heinrich Pestalozzi * Hans A. Pestalozzi Schools with that name:* Colegio Pestalozzi, Argentina* Pestalozzi-Gymnasium Biberach, Germany* Kinderdorf Pestalozzi, Switzerland...
Biography
Catherine Goldstein, Neither public nor private: mathematics in early modern France. Abrégée recherche de Marie Crous, pour tirer la solution de toute proposition d'arithmétique, dépendantes des règles y contenues ; avec quelques propositions sur les changes, escomptes, intérêt, compagnie, associations, paiements, départements de deniers, mélanges, bureau des monnaies et toisages, divisé en trois parties. ENsemble un avis sur les dixmes ou dixièmes du sieur Stevin, à Paris, chez Jacques Auvray. 1661. M. Olry TerquemOlry Terquem
Olry Terquem was a French mathematician, best known for his work in geometry, where he proved Feuerbach's theorem about the nine-point circle of a triangle...
, publié par T. Bachelier, article sur Marie Crous p. 200 et seq. Ou Nouvelles annales de mathématiques, Volume 14 p. 200 et seq (1852). Georges Maupin, Opinions et curiosités touchant la mathématique (deuxième série) d'après les ouvrages français des XVIe, XVIIe et XVIIIe siècle, édité à Paris chez Naud (1898). pp. 230–243.