列奥纳多·达·芬奇Leonardo da Vinci

列奥纳多·达·芬奇在家中接受教育，接受了通常的读、写、算初等教育。1467年，他成为学徒，学习绘画、雕塑并获得技术和机械技能。1472年，他被佛罗伦萨的画家行会接纳，但直到1477年他仍继续作为学徒工作。从那时起，他在佛罗伦萨作为画家独立工作。在此期间，他已经绘制了水泵、军事武器和其他机器的草图。

在1482年至1499年间，达·芬奇服务于米兰公爵。在公爵的职员名单中，他被描述为painter and engineer of the duke。在为公爵服务期间，他不仅完成了六幅画作，还就建筑、防御工事和军事事务提供建议。他还被认为是一位水力和机械工程师。

在米兰期间，达·芬奇对几何学产生了兴趣。他阅读了Leon Battista 莱昂·巴蒂斯塔·阿尔伯蒂关于建筑的书籍以及Piero della 皮耶罗·德拉·弗朗西斯卡的On Perspective in Painting。他为卢卡·帕西奥利的Divina proportione绘制插图，并继续与卢卡·帕西奥利合作，据报告，由于他如此专注于几何学，以至于忽视了他的绘画。

达·芬奇研究了欧几里得和卢卡·帕西奥利的Suma，并开始了自己的几何研究，有时给出机械解法。他给出了squaring the circle的几种方法，同样使用了机械方法。大约在这个时候，他写了一本关于力学基础理论的书，该书于1498年左右在米兰出版。

达·芬奇确实意识到了制造望远镜的可能性，并在1490年写成的Codex Atlanticus中谈到

……制造镜片以看到放大的月亮。

在后来一部约1513年写成的著作Codex Arundul中，他说，

……为了观察行星的性质，打开屋顶，把单颗行星的像投射到凹面镜的底部。由镜底反射的行星像将把行星表面显示得大为放大。

关于这段引文以及达·芬奇关于宇宙的更多思想的更多细节，见[28]。他理解月球靠反射太阳光而发光这一事实，并正确地把“新月抱旧月”解释为月球表面被地球反射的光所照亮。他认为月球与地球相似，有海和陆地区域。

1499年，法国军队进入米兰，公爵战败。几个月后，达·芬奇与卢卡·帕西奥利一起离开米兰。他前往曼图亚、威尼斯，最后到达佛罗伦萨。尽管他不断受到作画的压力，但数学研究使他在大部分时间里远离绘画活动。他曾一度受雇于切萨雷·博尔贾，担任

高级军事建筑师和总工程师。

到1503年，他回到佛罗伦萨，为将阿尔诺河改道到比萨后方以协助佛罗伦萨人正在进行的围城战的工程提供建议。随后他制定了让佛罗伦萨通向大海的运河计划。这条运河从未建成，阿尔诺河也从未改道。

1506年，达·芬奇第二次回到米兰。再次，他的科学工作优先于绘画，他涉足流体动力学、解剖学、力学、数学和光学。

1513年，法国人被逐出米兰，达·芬奇再次迁移，这一次到了罗马。然而，他在罗马似乎又过着孤独的生活，更专注于数学研究和他工作室里的技术实验，而非绘画。在三年郁郁寡欢之后，达·芬奇接受了国王弗朗索瓦一世的邀请，前往法国为其效力。

法国国王授予达·芬奇头衔

国王的首席画家、建筑师和机械师

但似乎让他随心所欲。这意味着达·芬奇除了完成手头的一些作品St. John the Baptist, Mona Lisa和Virgin and Child with St Anne之外，没有作画。达·芬奇大部分时间都在整理和编辑他的科学研究。

Leonardo da Vinci was educated in his father's house receiving the usual elementary education of reading, writing and arithmetic. In 1467 he became an apprentice learning painting, sculpture and acquiring technical and mechanical skills. He was accepted into the painters' guild in Florence in 1472 but he continued to work as an apprentice until 1477. From that time he worked for himself in Florence as a painter. Already during this time he sketched pumps, military weapons and other machines.

Between 1482 and 1499 Leonardo was in the service of the Duke of Milan. He was described in a list of the Duke's staff as a painter and engineer of the duke. As well as completing six paintings during his time in the Duke's service he also advised on architecture, fortifications and military matters. He was also considered as a hydraulic and mechanical engineer.

During his time in Milan, Leonardo became interested in geometry. He read Leon Battista Alberti's books on architecture and Piero della Francesca's On Perspective in Painting. He illustrated Pacioli's Divina proportione and he continued to work with Pacioli and is reported to have neglected his painting because he became so engrossed in geometry.

Leonardo studied Euclid and Pacioli's Suma and began his own geometry research, sometimes giving mechanical solutions. He gave several methods of squaring the circle, again using mechanical methods. He wrote a book, around this time, on the elementary theory of mechanics which appeared in Milan around 1498.

Leonardo certainly realised the possibility of constructing a telescope and in Codex Atlanticus written in 1490 he talks of

... making glasses to see the Moon enlarged.

In a later work, Codex Arundul written about 1513, he says that

... in order to observe the nature of the planets, open the roof and bring the image of a single planet onto the base of a concave mirror. The image of the planet reflected by the base will show the surface of the planet much magnified.

See [28] for more details of this quotation and more of Leonardo's ideas about the Universe. He understood the fact that the Moon shone with reflected light from the Sun and he correctly explained the 'old Moon in the new Moon's arms' as the Moon's surface illuminated by light reflected from the Earth. He thought of the Moon as being similar to the Earth with seas and areas of solid ground.

In 1499 the French armies entered Milan and the Duke was defeated. Some months later Leonardo left Milan together with Pacioli. He travelled to Mantua, Venice and finally reached Florence. Although he was under constant pressure to paint, mathematical studies kept him away from his painting activity much of the time. He was for a time employed by Cesare Borgia as a

senior military architect and general engineer.

By 1503 he was back in Florence advising on the project to divert the River Arno behind Pisa to help with the siege of the city which the Florentines were engaged in. He then produced plans for a canal to allow Florence access to the sea. The canal was never built nor was the River Arno diverted.

In 1506 Leonardo returned for a second period in Milan. Again his scientific work took precedence over his painting and he was involved in hydrodynamics, anatomy, mechanics, mathematics and optics.

In 1513 the French were removed from Milan and Leonardo moved again, this time to Rome. However he seems to have led a lonely life in Rome again more devoted to mathematical studies and technical experiments in his studio than to painting. After three years of unhappiness Leonardo accepted an invitation from King Francis I to enter his service in France.

The French King gave Leonardo the title of

first painter, architect, and mechanic of the King

but seems to have left him to do as he pleased. This means that Leonardo did no painting except to finish off some works he had with him, St. John the Baptist, Mona Lisa and the Virgin and Child with St Anne. Leonardo spent most of his time arranging and editing his scientific studies.