威廉·施卡德Wilhelm Schickard

威廉·施卡德的名字有时写作Schickhard或Schickhardt或Schickart。他的母亲是Margarete Gmelin，一位路德会牧师的女儿，他的父亲是爱德华·卢卡斯 施卡德。施卡德家族原籍杰森·约翰·拿骚郡，但在15世纪中叶南迁。卢卡斯 施卡德的父亲是一名雕塑家，在斯图加特以南约30公里的黑伦贝格定居。卢卡斯 施卡德接受培训成为木匠，他的兄弟Heinrich Schickard也是如此，后者是施卡德的叔叔。Heinrich Schickard成为建筑师，后来成为德国西南部文艺复兴的主要建筑师。施卡德在黑伦贝格长大，但年幼时获得奖学金，进入图宾根以北的贝本豪森修道院学校就读。

在贝本豪森的修道院学校就读后，他进入了图宾根大学。他于1609年获得第一个学士学位，随后于1611年获得硕士学位，两者都是在神学和东方语言领域，并且他继续在图宾根学习这些科目直到1613年。在图宾根学习期间，米夏埃尔·梅斯特林教他数学和天文学。1613年，施卡德成为路德宗牧师，并被分配到图宾根周边城镇的教堂。1614年，他被任命为尼尔廷根的执事。他继续在路德宗教会工作直到1619年。正是在他担任路德宗牧师期间，他第一次遇到了约翰内斯·开普勒，后者来到图宾根支持他被指控巫术的母亲。约翰内斯·开普勒当时正在撰写他的Harmony of the World，在遇到施卡德后，他对他的能力印象深刻，以至于请他为此书做一些版画和木刻，还请他协助计算一些表格。这并不像乍听起来那么令人惊讶，因为在他的其他技能中，施卡德作为木刻和铜版雕刻师都很有名。[3]的作者写道：——

[施卡德]同意在木版上绘制并雕刻《概要》第二部分的图形。然而，克吕格[约翰内斯·开普勒的出版商]，总是准备干涉约翰内斯·开普勒的计划，规定雕刻必须在奥格斯堡完成。施卡德在1617年12月底将第4卷和第5卷的三十七个木版送到奥格斯堡。……1621年6月，约翰内斯·开普勒在法兰克福[安排第5-7卷的出版]。施卡德雕刻了最后两卷的图形（雕刻由他的一个表亲完成）。

正是他与约翰内斯·开普勒相关的工作促使他考虑制造一台机器，将他正在做的天文计算机械化。不过，这要稍晚一些才发生，所以我们将首先描述施卡德作为希伯来语教授的生活的下一阶段。

1619年，他离开路德教会的工作，被任命为图宾根大学的希伯来语教授。施卡德是一位全才科学家，教授阿拉米语和希伯来语等圣经语言。他努力改进自己学科的教学，展现出非凡的创新精神。他坚信，作为教授，让他的学生更容易学习希伯来语是他工作的一部分。他帮助学生的一项发明是“Hebraea 吉安-卡洛·罗塔”。这个机械装置通过两个叠放的旋转圆盘来展示希伯来语动词的变位，相应的变位形式出现在窗口中。他还创造了Horologium Hebraeum Ⓣ（希伯来钟），这是一本分为24章的希伯来语教科书，每章包含可在一小时内学完的内容。1627年，他为德国希伯来语学生写了另一本教科书Hebräischen Trichter Ⓣ（希伯来漏斗）。然而，他的研究范围很广，除了希伯来语，还包括天文学、数学和测量学。在天文学中，他发明了一种用于 Astroscopium中星图的圆锥投影。他1623年的星图由沿至日子午线切割的圆锥组成，极点位于圆锥的中心和顶点。他还在制图方面取得了重大进展，展示了如何制作比当时可用的地图精确得多的地图。他在制图学方面最著名的著作是Kurze Anweisung, wie künstliche Landtafeln auss rechtem Grund zu machen Ⓣ（制作陆地地图的简要指导）（1629年）。早在布莱兹·帕斯卡和哥特弗里德·威廉·莱布尼茨之前很久，施卡德就在1623年发明了一种计算器“Rechenuhr”。他在1623年9月20日写信给约翰内斯·开普勒：-

你通过计算所做的工作，我刚刚尝试通过机械方式来完成。我构思了一台由十一个完整齿轮和六个不完整链轮组成的机器；它根据给定的数字即时自动计算，进行加、减、乘、除。你会喜欢看到这台机器如何自发地将十或一百向左累积和进位，反之，如果它在做减法，又如何做相反的操作……

约翰内斯·开普勒显然有兴趣拥有一台施卡德的计算器，因为施卡德给出了为他建造一台的指示。然而，这台半成品计算机在一场火灾中被毁，正如他在1624年2月25日写给约翰内斯·开普勒的另一封信中所解释的那样。在这封信中，他给出了机器构造方式的一些更多细节：-

……下次我会寄给你一份关于这台算术机器设计的更详细描述；总之，它的工作原理如下：aaa是垂直圆柱上的按钮，上面有乘法表的数字，可以根据需要在为滑块bbb提供的窗口中显示。刻度盘ddd连接在内部齿轮上，每个齿轮有十个齿，其啮合方式使得如果右边的轮子转十圈，它左边的轮子只转一圈；如果最右边的第一个轮子转一百圈，左边第三个轮子转一圈，依此类推。所有轮子都朝同一方向旋转，因此需要使用另一个相同大小的轮子，它与其左边的轮子永久啮合，但不与其右边的轮子啮合，这在建造过程中需要特别注意。每个轮子上标记的数字显示在中央板的开口ccc中。最后，位于底座上方的按钮eee用于在开口fff中显示操作过程中需要使用的数字。如果使用实际的仪器，这个简要描述会更容易理解。我曾向当地人Johan Pfister订购为你建造一台机器；但当完成一半时，这台机器连同我的一些其他东西，特别是一些金属板，在三天前夜间不知不觉发生的火灾中被毁。我对这一损失感到非常痛心，尤其是因为无法很快生产出替代品。

Kistermann 研究了 施卡德 的计算器的设计，并在 [9] 中解释了该机器的“架构”。施卡德 在他的机器中使用了缩简乘法，Kistermann 指出，1600 年时大多数科学界人士都不知道这种方法，只有少数科学家（但包括 约斯特·伯基、约翰内斯·开普勒 和 施卡德）了解这一技术。在 [10] 中，Kistermann 考虑了 施卡德 的计算器是否有实际用途。计算器的草图保存在 施卡德 和 约翰内斯·开普勒 留下的手稿中。然而，这些草图直到 1935 年才被重新发现，当时是在研究 约翰内斯·开普勒 的生平时找到的。在这个阶段，它们的意义尚未被理解，但二十年后人们意识到这是 施卡德 所描述的计算机的草图。Bruno von Freytag Löringhoff 在 1957 年至 1960 年间利用草图和 施卡德 信件中的描述建造了这台计算机。然后他测试了可能的计算范围，以试图确切确定 施卡德 建造这台计算机器的目的。Von Freytag Löringhoff 发现它运行良好，特别适合执行十七世纪天文学家所需的天文计算；更多细节见 [4]。事实上，我们知道 施卡德 也写信给 约翰内斯·开普勒，提出了一种计算星历表的机械方法。

1631年，施卡德 改换了学科，被任命为图宾根大学的数学与天文学讲席，该职位因其老师 米夏埃尔·梅斯特林 去世而空缺。然而，这一变动并不意味着他兴趣的重大转变，因为如上所述，他一直对广泛的主题抱有广泛的兴趣。例如，他讲授建筑学、筑城学和水力学。他还承担了符腾堡公国的土地测量工作，这涉及首次在地测中使用 威理博·斯涅尔 的三角测量法；更多细节见 [6]。作为天文学教授，施卡德 就这一主题授课，并对月球的运动进行研究。他于1631年出版了 Ephemeris Lunaris，该书使得可以在任何时间确定月球的位置。我们应当注意，在教会试图坚持地球是宇宙中心的时代，施卡德 是日心体系的坚定支持者。我们上文提到了 施卡德 与 约翰内斯·开普勒 的通信，但他还与许多其他天文学家通信，包括 伊斯梅尔·布里阿德 和 皮埃尔·伽桑狄。

三十年战争（1618-1648）影响了施卡德晚年的大部分时光。1634年9月的讷德林根战役后，得到大量西班牙军队增援的天主教军队决定性地击败了新教军队，获胜的军队占领了蒂宾根。军队带来了腺鼠疫，蒂宾根的人口受到严重影响。在接下来的一年里，施卡德的妻子和所有孩子都死于鼠疫。他是家中最后一个死于腺鼠疫的人，去世日期或如上所述，也可能早一天。

施卡德的贡献在他生前未得到充分认可，今天人们以蒂宾根大学的施卡德-施卡德-计算机科学研究所和蒂宾根的施卡德-施卡德-学校来纪念他。

Wilhelm Schickard's name is sometimes written as Schickhard or Schickhardt or Schickart. His mother was Margarete Gmelin, the daughter of a Lutheran pastor, and his father was Lucas Schickard. The Schickard family was originally from the County of Nassau but had moved south in the middle of the 15th century. Lucas Schickard's father, who was a sculptor, had settled in Herrenberg about 30 km south of Stuttgart. Lucas Schickard trained to be a carpenter, as did his brother Heinrich Schickard, who was Wilhelm's uncle. Heinrich Schickard became an architect and went on to become the main architect of the Renaissance in south-western Germany. Wilhelm was brought up in Herrenberg but, at an early age, won a scholarship to attend the monastery school in Bebenhausen, just north of Tübingen.

After attending the monastery school in Bebenhausen, he entered the University of Tübingen. He received his first degree of B.A. in 1609, followed by an M.A. in 1611, both in theology and oriental languages, and he continued to study these topics at Tübingen until 1613. While studying at Tübingen, he was taught mathematics and astronomy by Michael Mästlin. In 1613 Schickard became a Lutheran minister and was assigned to churches in towns around Tübingen. In 1614 he was appointed deacon in Nürtingen. He continued this work with the Lutheran Church until 1619. It was during his time as a Lutheran minister that he first met Johannes Kepler who came to Tübingen to support his mother who had been charged with witchcraft. Kepler was working on his Harmony of the World at this time and, after meeting Schickard, he was so impressed with his abilities that he asked him to do some engravings and woodcuts for the book and also asked him to assist in calculating some tables. This is not as surprising as it might first sound since, among his other skills, Schickard was renowned as an engraver both in wood and in copperplate. The authors of [3] write:-

[Schickard] agreed to draw and engrave the figures of the second part of the 'Epitome' on woodblocks. Yet Krüger [Kepler's publisher], always ready to interfere with Kepler's plans, stipulated that the carving had to be done in Augsburg. Schickard sent thirty-seven woodblocks for books 4 and 5 to Augsburg towards the end of December 1617. ... In June 1621 Kepler was in Frankfurt [arranging for the publication of books 5-7]. Schickard engraved the figures for the last two books (the carving was done by one of his cousins).

It was his work with Kepler which prompted him to think about making a machine to mechanise the astronomical calculations he was doing. This was to come a little later, however, so first we will describe the next phase of Schickard's life as a professor of Hebrew.

In 1619 he left his work in the Lutheran Church when he was appointed as the professor of Hebrew at the University of Tübingen. Schickard was a universal scientist and taught biblical languages such as Aramaic as well as Hebrew. His efforts to improve the teaching of his subject show remarkable innovation. He strongly believed that, as the professor, it was part of his job to make it easier for his students to learn Hebrew. One of his inventions to assist his students was the 'Hebraea Rota'. This mechanical device displayed conjugation of Hebrew verbs by having two rotating discs laid on top of each other, the respective forms of conjugation appearing in the window. He also created the Horologium Hebraeum Ⓣ, a textbook of Hebrew divided into 24 chapters, each chapter containing material which could be learnt in an hour. He wrote another textbook, the Hebräischen Trichter Ⓣ, for German students of Hebrew, in 1627. However, his research was broad and, in addition to Hebrew, included astronomy, mathematics and surveying. In astronomy he invented a conic projection for star maps in the Astroscopium. His star maps of 1623 consist of cones cut along the meridian of a solstice with the pole at the centre and apex of the cone. He also made significant advances in mapmaking, showing how to produce maps which were far more accurate than those which were currently available. His most famous work on cartography was Kurze Anweisung, wie künstliche Landtafeln auss rechtem Grund zu machen Ⓣ (1629). Long before Pascal and Leibniz, Schickard invented a calculating machine, the 'Rechenuhr', in 1623. He wrote to Kepler on 20 September 1623:-

What you have done by calculation I have just tried to do by way of mechanics. I have conceived a machine consisting of eleven complete and six incomplete sprocket wheels; it calculates instantaneously and automatically from given numbers, as it adds, subtracts, multiplies and divides. You would enjoy seeing how the machine accumulates and transports spontaneously a ten or a hundred to the left and, vice-versa, how it does the opposite if it is subtracting ...

Kepler clearly showed an interest in having one of Schickard's calculators since Schickard gave instructions for one to be built for him. However, the half-built computer was destroyed by fire as he explained in another letter to Kepler written on 25 February 1624. In this letter he gives some more details of the way the machine is constructed:-

... On another occasion I will send you a more detailed description of the design of this arithmetic machine; in summary, it works as follows: aaa are the buttons on the vertical cylinders with the digits of the multiplication table, which can be displayed at will in the windows provided for the slides bbb. The dials ddd are attached to internal toothed wheels, each one having ten teeth geared in such a way that, if the wheel on the right makes ten turns, the wheel on its left makes only one turn; and if the first wheel on the right hand side makes one hundred turns, the third wheel on the left makes one turn, and so on. All the wheels rotate in the same direction making necessary the use of another wheel of the same size geared permanently to the wheel at its left, but not with the one at its right, which requires special attention during its construction. The digits marked on each wheel are displayed in the openings ccc of the central plate. Finally, the buttons eee, located over the base, are used to display in the openings fff the numbers that need to be used during the operations. This brief description would be better understood by using the actual instrument. I had placed an order with a local man, Johan Pfister, for the construction of a machine for you; but when half finished, this machine, together with some other things of mine, especially several metal plates, fell victim to a fire which broke out unseen during the night three days ago. I take the loss very hard, especially since there is no time to produce a replacement soon.

Kistermann studied the design of Schickard's calculator and explains the "architecture" of the machine in [9]. Schickard used the abridged multiplication for his machine which, Kistermann points out, was unknown to most of the scientific community in 1600, with only a handful of scientists (but including Jost Bürgi, Kepler and Schickard) having knowledge of this technique. In [10] Kistermann considers whether Schickard's calculator was of practical use. Sketches of the calculator have been preserved in the manuscripts left by Schickard and Kepler. These however, were not rediscovered until 1935 when they were found during research into Kepler's life. At this stage their significance was not understood, but twenty years later it was realised that it was a sketch of the computer described by Schickard. Bruno von Freytag Löringhoff constructed the computer between 1957 and 1960 using the sketch and the descriptions in Schickard's letters. He then tested the range of calculations which were possible to try to ascertain exactly what purpose Schickard had in building the calculating machine. Von Freytag Löringhoff discovered that it worked well and was particularly suited to carry out the astronomical calculations which were necessary for astronomers of the seventeenth century; see [4] for further details. In fact we know that Schickard also wrote to Kepler suggesting a mechanical means to calculate ephemerides.

In 1631 Schickard had rather a change of subject, being appointed to the chair of mathematics and astronomy at the University of Tübingen left vacant by the death of his teacher Michael Mästlin. This change did not signify a major shift in his interests, however, for as we indicated above he had always had broad interests across a wide range of subjects. For example, he lectured on architecture, fortification, and hydraulics. He also undertook land surveying of the duchy of Württemberg which involved the first use of Willebrord Snell's triangulation method in geodesic measurements; see [6] for further details. As professor of astronomy Schickard lectured on the topic and undertook research into the motion of the moon. He published Ephemeris Lunaris in 1631 which allowed the position of the moon to be determined at any time. We should note that, at a time when the Church was trying to insist that the Earth was at the centre of the universe, Schickard was a staunch supporter of heliocentric system. We have mentioned above Schickard's correspondence with Kepler but he corresponded with many other astronomers including Ismael Boulliau and Pierre Gassendi.

The Thirty Years War (1618-1648) affected much of the later part of Schickard's life. Following the Battle of Nördlingen in September 1634, when the Catholic army augmented by many Spanish troops won a decisive victory over the Protestant army, the victorious troops occupied Tübingen. The troops brought with them the bubonic plague and the population of Tübingen was badly affected. Over the next year Schickard's wife and all his children died from the plague. He was the last of the family to succumb to the bubonic plague, dying either on the day given above or, possibly, one day earlier.

Although Schickard's contributions were not fully recognised during his lifetime, be is remembered today with the Wilhelm-Schickard-Institut für Informatik at the University of Tübingen and the Wilhelm-Schickard-Schule in Tübingen.