Gaspard de Prony

Gaspard de Prony的姓氏是Riche，de Prony头衔是他的父母买来的。事实上，de Prony的弟弟一直以Riche这个名字为人所知。De Prony在杜省的Toissei本笃会学院接受教育。1776年，他从那里进入桥梁与道路学校学习工程学。1779年，他作为最优秀的学生毕业，并在巴黎又呆了一年，按照桥梁与道路学校校长的吩咐行事：-

M de Prony……你要专心致志地深入掌握你的专业，因为你注定要成为École des Ponts et Chaussés的负责人。

1780年，他成为École des Ponts et Chaussés的一名工程师，在法国多个不同地区工作三年后，他于1783年回到巴黎的École des Ponts et Chaussés。同年，他在Académie des Sciences上发表了他的第一部重要著作，研究拱上的力。加斯帕尔·蒙日对这篇论文印象深刻，并意识到de Prony是一个极具潜力的人。

1785年，de Prony前往英格兰，参与一个旨在精确测量格林尼治天文台与巴黎天文台相对位置的项目。两年后，他晋升为桥梁与道路学校的监察员。大约在这段时间，他参与了巴黎路易十六桥的建造工作，该桥现称为协和桥。

1790年再次晋升后，次年他被任命为桥梁与道路学校的总工程师。这次晋升是路易十六桥通车的成果。

同样在1791年前后，de Prony与Pierre Girard一起研究几何学。然后在1792年，de Prony开始了一项重大任务，即编制对数表和三角函数表，即Cadastre。在阿德里安-马里·勒让德、拉扎尔·卡诺和其他数学家的协助下，以及70到80名助手的参与下，这项工作历时数年，于1801年完成。这些表，见[2]：-

……规模庞大，数值计算到十四到二十九位小数。每份包括十八对开卷，外加一卷数学程序。

让如此庞大的著作出版是另一回事。谈判持续了数年，直到1809年，似乎它们将要问世。出版商写道：-

如果M de Prony没有幸运地想到应用强大的分工方法，构思出将制表过程中漫长而艰苦的部分简化为简单加减法的方法，当代人将永远无法见证这部不朽著作的完成……

然而这些表格从未完整出版，直到本世纪末才有一部分问世。在法国财政状况不佳的时期，印刷成本实在太高了。

1794年，公共工程中央学校成立，由拉扎尔·卡诺和加斯帕尔·蒙日领导。1795年它更名为巴黎综合理工学院，此时de Prony无疑是主要讲座之一。他被列为该大学首批教师之一：-

Prony，分析学讲师，地籍局局长，研究所成员。年薪6,000法郎。校内住宿...

De Prony在巴黎综合理工学院讲授的课程被出版，包括他关于水力学的讲座。

1798年，de Prony拒绝了拿破仑要求他加入远征埃及军队的请求。约瑟夫·傅里叶、加斯帕尔·蒙日和艾蒂安-路易·马吕斯已同意加入远征军，拿破仑对de Prony不愿前来感到愤怒。这确实意味着de Prony未能获得他应得的来自拿破仑的荣誉，但de Prony的妻子是约瑟芬的密友，这很可能使de Prony免于更糟的境遇。

1798年，de Prony实现了被任命为桥梁与道路学校校长的抱负。他对这一职位的渴望几乎肯定是他拒绝加入拿破仑的主要原因。作为校长，他开始撰写多部关于数学物理的重要著作。他成为经度局成员，并在1810年和1811年，根据他在巴黎综合理工学院的讲座，又出版了两部重要著作，即Leçons de Mécanique AnalytiqueⓉ（分析力学教程）和Sommaire des Leçons du Cours de MécaniqueⓉ（力学课程讲义概要）。

拿破仑战败后，法国的重组包括对1816年关闭的巴黎综合理工学院的重组。De Prony失去了在那里的教授职位，也没有进入重组委员会。然而，学校一重新开放，de Prony就被邀请担任考官，因此他保持了与学校的联系，但每年只需工作一个月。

de Prony最重要的科学发明之一是“de Prony制动器”，他于1821年发明了它，用于测量机器和发动机的性能。它基于Hachette的思想，是对Pierre Girard两年前使用的方法的相当大的改进。

de Prony职业生涯的最后部分更多地涉及教育而非行政。他进行的一场斗争，但未成功，是反对奥古斯丁·路易·柯西转向纯数学而远离de Prony坚信的应用数学。在[2]中，Margaret Bradley写道：-

...长期以来，对桥梁公路学校改革的呼声日益高涨，而他对此缺乏关注招致了严厉批评。他现在对学校的日常管理表现出更少的兴趣，而更倾向于科学。他对在巴黎综合理工学院改革数学教学的尝试失败感到失望，他曾在那里积极而坚定地努力对抗奥古斯丁·路易·柯西对理论的强调...Prony似乎对持续的斗争失去了信心，并且对自己的考官职责不那么尽责了。

Gaspard de Prony's family name was Riche, the de Prony title having been bought by his parents. In fact de Prony's younger brother was always known by the name Riche. De Prony was educated at the Benedictine College at Toissei in Doubs. From there he entered the École des Ponts et Chaussés in 1776 where he studied engineering. He graduated in 1779 as the top student and remained for a further year in Paris, doing as the head of the École des Ponts et Chaussés told him:-

M de Prony ... concern yourself with acquiring a deep knowledge of your art, for you are destined to become head of the École des Ponts et Chaussés.

In 1780 he became an engineer with the École des Ponts et Chaussés and after three years in a number of different regions of France he returned to the École des Ponts et Chaussés in Paris 1783. This was the same year he published his first major work in the Académie des Sciences on the forces on arches. Monge was impressed with this paper and realised that de Prony was someone of great potential.

In 1785 de Prony visited England on a project to obtain an accurate measurement of the relative positions of the Greenwich Observatory and the Paris Observatory. Two years later he was promoted to inspector at the École des Ponts et Chaussés. Around this time he was involved with the work on the Louis XVI Bridge in Paris which is now called the Pont de la Concorde.

Further promotion in 1790 was followed the next year by his being appointed Engineer-in-Chief of the École des Ponts et Chaussés. This promotion was as a result of the opening of the Louis XVI Bridge.

Also around 1791 de Prony was working on geometry with Pierre Girard. Then in 1792, de Prony began a major task of producing logarithmic and trigonometric tables, the Cadastre. With the assistance of Legendre, Carnot and other mathematicians, and between 70 to 80 assistants, the work was undertaken over a period of years, being completed in 1801. The tables were, see [2]:-

... vast, with values calculated to between fourteen and twenty-nine decimal places. Each copy consisted of eighteen folio volumes together with another volume of mathematical procedures.

Getting such a massive work published was another matter. Negotiations went on over a number of years until, in 1809, it seemed they would appear. The publisher wrote:-

The present generation would never have witnessed the end of this monumental work if M de Prony had not had the fortunate idea of applying the powerful method of division of labour, conceiving methods to reduce the long and laborious part of the production of the tables to simple additions and subtractions...

However the tables were never published in full and it was near the end of the century before even a part appeared. It was just too expensive to print at a time when France was not in the best of financial states.

In 1794 the École Centrale des Travaux Publics was founded by and was directed by Carnot and Monge. It was renamed the École Polytechnique in 1795 and de Prony was certainly one of the main lectures by this time. He is listed among the first teachers at the university as:-

Prony, lecturer in analysis, director of the Cadastre, member of the Institute. Annual salary 6,000 francs. Accommodation within the school...

De Prony's lectures given at the École Polytechnique were published, including his lectures on hydraulics.

In 1798 de Prony refused Napoleon's request that he join his army of invasion to Egypt. Fourier, Monge and Malus had agreed to be part of the expeditionary force and Napoleon was angry that de Prony would not come. It did mean that de Prony was to fail to receive the honours he deserved from Napoleon but de Prony's wife was a close friend of Joséphine and this probably saved de Prony from anything worse.

In 1798 de Prony achieved his ambition of being appointed director of the École des Ponts et Chaussés. His desire for this post was almost certainly a main reason for his refusing to join Napoleon. As director he began producing a number of important texts on mathematical physics. He became a member of the Bureau de Longitude and, in 1810 and 1811, he produced two further major texts from his lectures at the École Polytechnique, namely Leçons de Mécanique Analytique Ⓣ and Sommaire des Leçons du Cours de Mécanique Ⓣ.

After Napoleon was defeated the reorganisation in France included a reorganisation of the École Polytechnique which was closed during 1816. De Prony lost his position as professor there and was not part of the reorganisation committee. However, as soon as the school reopened, de Prony was asked to be an examiner so he continued his connection yet only had to work one month per year.

One of de Prony's most important scientific inventions was the 'de Prony brake' which he invented in 1821 to measure the performance of machines and engines. It was based on ideas of Hachette and was a considerable improvement on a method which Pierre Girard had used two years earlier.

The last part of de Prony's career was more involved with education rather than administration. One battle he fought, without success, was against Cauchy's move towards pure mathematics and away from the more applied mathematics which de Prony firmly believed in. In [2] Margaret Bradley writes:-

... there had long been an increasing demand for the reform of the École des Ponts et Chaussés and his lack of attention to this attracted severe criticism. He was now showing even less interest in the day to day running of the school, in favour of science. He was disillusioned by the failure of his attempts to reform mathematics teaching at the École Polytechnique, where he had made energetic and determined efforts to combat the emphasis on theory of A-L Cauchy ... Prony seems to have lost heart for the continuing struggle and to have been less conscientious with regard to his duties as examiner.