Wilhelm Schickard

You can never cross the ocean unless you have the courage to lose sight of the shore.
Cristoforo Colombo

Wilhelm Schickard, portrait from 1632
Wilhelm Schickard (Wilhelmus Schickart), Professor of Hebrew, Astronomy, and Mathematics – a portrait from 1632

One of the most important events in the life of the modest deacon of Nürtingen, Wilhelm Schickard, was his meeting in October 1617, with the great astronomer Johann Kepler. Obviously, during this meeting, Kepler immediately recognized the massive intellect of the young Wilhelm and encouraged his occasions with sciences, which led to the creation of the first mechanical calculator in the world (Schickard referred to it as Rechen Uhrcalculating meter or calculating clock).

It was not a casual meeting. Kepler, just like Schickard, had studied theology at Tübinger Stift (Kepler lived in Tübingen from 1589 till 1594) and worked as a Lutheran minister some 20 years before him, before devoting his life to mathematics and astronomy. Kepler visited Tübingen during one of his journeys in Württemberg, to see his old friend Michael Maestlin (1550-1631) (a famous German astronomer and mathematician, who used to be a mentor of Johann Kepler and just like Schickard and Kepler, was Magister of theology at Tübinger Stift from 1571 and worked some time as a Lutheran deacon) and others. It seems Schickard was recommended to Kepler just by Maestlin, who was Schickard’s teacher and precursor in the chair of astronomy. Maestlin probably was some kind of a patron for Schickard also (as he used to be for Kepler), because at that time there was no academic appointment without patronage.

Johannes Kepler in 1610
Johannes Kepler in 1610

Kepler wrote in his diary about his first impressions of Schickard—”In Nürtingen I met also an excellent talent, a math-loving young man, Wilhelm, a very industrious mechanic and lover of oriental languages.” From this moment on, Schickard entered into a close friendship and busy correspondence with Kepler until his death, made science investigations for him, and took care of Kepler’s son—Ludwig, who was a student in Tübingen and received a Master of Arts degree in 1629, created by Kepler’s request figures and copper plates, and helped for the printing of Kepler’s renown books.

Kepler was a great admirer of the logarithms of Napier. When in 1617 he first saw a copy of Napier’s book on logarithms, he didn’t fully understand them. He wrote to Schickard saying that some Scottish nobleman had come up with a way of turning all multiplications and divisions into additions and subtractions but later remarked that he doubted it would work properly. About a year later he reconsidered the concept and became so enthusiastic, that he wrote to Napier, and dedicated him his Ephemerides.

Unfortunately, the calculating machine, designed by Schickard around 1623, didn’t manage to survive to the present day. Only three documents about this machine have been found till now—two letters from Schickard to Kepler, and a sketch of the machine with instructions to the mechanic.

The two letters were discovered by a famous biographer of Kepler—Max Caspar, who worked in 1935 in the archive of Kepler, kept in the Pulkovo Observatory, near S. Peterburg, Russia (Kepler’s manuscripts were bought by order of the Empress of Russia Екатерина II Великая (Catherine the Great) in 1774). While searching through a copy of Kepler’s Rudolphine Tables, Caspar found a slip of paper, that had seemingly been used as a bookmark. It was this slip of paper that contained Schickard’s original drawings of the machine (from the second letter to Kepler). Later Max Caspar stumbled upon the other pages of the two letters.
In the 1950s another biographer of Kepler—Dr. Franz Hammer (1898-1969), made a connection between the two letters from Pulkovo and a sketch of a machine (along with instructions to the mechanic Johann Pfister), described in Schickard’s manuscripts (Schickard sketchbook), kept in Württembergischen Landesbibliothek in Stuttgart (see the figures below).

The sketch from the Württembergischen Landesbibliothek in Stuttgart
The sketch from the Württembergischen Landesbibliothek in Stuttgart
The instructions to the mechanician from the Württembergischen Landesbibliothek in Stuttgart
The instructions to the mechanic from Württembergischen Landesbibliothek

Caspar and Hammer however were not the first men, who noticed the machine of Schickard. Who was the first?
In 1718 one of the first biographers of Kepler—the German philosopher, theologian, and mathematician Michael Gottlieb Hansch (1683-1749), published a book of letters of Kepler, which includes the two letters from Schickard to Kepler. There is even a marginal note of the publisher Schickardi machina arithmetica in the second letter, obviously on the calculating machine.
In 1787, in the book “An account of the life, writings, and inventions of John Napier, of Merchiston”, the author—David Erskine, Earl of Buchan, mentioned that …Shickartus in a letter to Kepler, written in the year 1623, informs him that he had lately constructed a machine consisting of eleven entire and six mutilated little wheels, by which he performed the four arithmetical operations.
In 1899 Stuttgart’s surveying magazine Stuttgarter Zeitschrift für Vermessungswesen published an old article for the topography in Württemberg, Germany, written many years ago and probably published in other editions, by the famous German scientist Johann Gottlieb Friedrich von Bohnenberger (1765–1831). In this article, the name of Schickard is mentioned several times, not only concerning his important contribution to the field of topography but it is mentioned also that …it is strange, that nobody admitted, that Schickard invented a calculating machine. In 1624 he ordered a copy for Kepler, but it was destroyed in a night fire. Bohnenberger (known mainly as the inventor of the gyroscope effect), just like Schickard, studied and later was appointed a professor of mathematics and astronomy at the University of Tübingen in 1798.
In 1912 the yearly German magazine Nachrichten des Württembergischen Vermessungstechnischen Vereins published the sketch and the notes of the machine from the Württembergischen Landesbibliothek. The author of the article A. Georgi was however probably not aware of the two letters of Schickard, but only with the note of Bohnenberger. He even claimed, that Leibnitz was aware of the machine of Schickard and accused him of plagiarism, which is unbelievable.
In April 1957, Hammer announced his discovery during the conference about the history of mathematics in Oberwolfach, Germany. From this moment on, gradually it was made known to the general public, that namely Schickard, but not Blaise Pascal, is the inventor of the first mechanical calculating machine.

In 1960 Mr. Bruno v. Freytag Löringhoff (1912-1996), a professor of philosophy at the University of Tübingen, created the first replica of Schickard’s machine.

A replica of the Schickard's machine, created by Bruno v. Freytag Löringhoff in 1960 (© Universität Tübingen)
A replica of Schickard’s machine, created by Bruno v. Freytag Löringhoff in 1960 (© Universität Tübingen)

The first letter—Wilhelm Schickard to Kepler in Linz, 20. September 1623, includes (letters are written in the Latin language, which was the international language of science and scholarship in Central and Western Europe until the 17th century):

…Porro quod tu logistice, idem ego mechanice nuper tentavi, et machinam extruxi, undecim integris et sex mutilatis rotulis constantem, quae datos numeros statim άώτομάτος computet, addat, subtrahat, multiplicet, dividatque. Rideres clare, si praesens cerneres, quomodo sinistros denarium, vel centenarium supergressos, sua sponte coacervet, aut inter subtrahendum ab eis aliquid suffuretur…

In English, it sounds like—I have tried to discover a mechanical way for performing calculations, which you have done manually till now. I constructed a machine, that includes eleven full and six partial pinion wheels, which can calculate automatically, to add, subtract, multiply, and divide. You would rest satisfied if you could see how the machine accumulates and shifts to the left tens and hundreds, and makes the opposite shift during a subtraction…

From 1612 to 1626, Kepler lived in Linz, Austria, where he worked as a mathematics teacher and as an astrologer. In this period (1623), he was completing his famous Tabulae Rudolphinae and certainly needed such a calculating instrument. He must have written back asking for a copy of the machine for himself, because the second letter, dated 25 February 1624, includes a description of the machine with two drawings and bad news about a fire, which destroyed the machine:

…Arithmeticum organum alias delineabo accuratius, nunc et festinate hoc habe, aaa sunt capitella cylindrorum erectorum, quibus multiplicationes digitorum inscriptae, et prominent, quantum ijs opus est, per fenestellas bbb ductiles, ddd intus habent affixas rotulas 10 dentium, sic contextas, vt mota qualibet dextra decies, proxima sinistra semel; aut illâ 100 vicibus circumactâ, tertia semel etc. promoveatur. Et quidem in eandem partem; quod vt praestarem, intermediâ consimilj h opus fuit.
(A marginal note) Quaelibet intermedia omnes sinistras movet, debitâ proportione; nullam verò dextram, quod singularj cauitione indiguit. (End of the note) Quotus eorum prominet per foramina ccc in scamno medio, tandem in pavimento inferiorj e vertebras et f similiter foramina pro apparitione numerorum notat, quibus inter operandum usus est. Sed ista sic tumultuariè scribj nequeunt, facilius ex autopsiâ cognoscentur. Et curaveram tibj jam exemplar confierj apud Joh. Pfisterum nostratem, sed illud semiperfectum, vna cum alijs quibusdam meis, praecipuè aliquot tabellis aeneis conflagravit ante triduum, in incendio noctu et ex improsivo ibj coorto, quod Mütschlinus referre amplius sciet. Harum jacturam admodum aegre fero, praesertum nunc quando non vacat alia reficere tam cito.

The first drawing from the second letter to Kepler
The first drawing from the second letter to Kepler

In English—…I will describe the computer more precisely some other time, now I don’t have enough time: aaa are the upper faces of vertical cylinders (see the upper figure), whose side surfaces are inscribed with multiplication tables. The digits of these tables can be looked out of the windows bbb of a sliding plate. From the inner side of the machine to the disks ddd are attached wheels with 10 cogs, and each wheel is clutched with a similar wheel in a manner that, provided some of the right wheels spin round ten revolutions, the left wheel will make one revolution, or provided the first wheel spins round 100 revolutions, the third wheel to the left will make one revolution. For the revolutions of the wheels to be in the same direction, intermediate wheels h are necessary.
(A marginal note) Each intermediate wheel moves to the left needed carry, but not to the right, which made special caution measures necessary.

The small second drawing from the second letter to Kepler
The second drawing from the second letter

The digits, inscribed upon each wheel, can be looked out of the windows ccc of the middle bank. At the end of the lower bank are arranged rotating heads eee, used for the recording of numbers, which are the result of the calculations, and their digits can be looked out of the windows fff. I have already ordered a copy for you to our Johann Pfister, together with some other things for me, especially some copper plates, but when the work was half finished, yesterday night a fire burst out and everything burnt out, as Maestlin informed you. I take this loss very heavily because there is no time for its replacement.

Schickard obviously was not satisfied with the work of the mechanic, involved in the production of the device, because the note to Pfister begins (old German language is used):
Rechen Uhr betreffs.
1. Die zän seind gar vngleich und vnfleißig…

(which means in English, kindly translated by Mr. Stephan Weiss, www.mechrech.info):
Concerning Calculating Clock,
1. The teeth are inequally made and don’t work. Sometimes more than a tenth part is driven, sometimes less. 20 teeth would be better.
2. The front eccentric smooth disk drags a little, it should be turned.
3. (NB) The single tooth (note: for the carry of tens) should not be placed in the middle between two others. Should it touch right onto a numeral tooth, it will push the number forward twice.
(NB) 4. Only the 0, and also the 9 should move the left number, the first when subtracting, and the next when adding.

This is why the numbers must be written in this way:
1. Start on the right with disc 1, turn right, where the disc starts to engage, write 9 on top, then turn to the left, where it starts to move and write 0 on top. The rest is self-explanatory.
2. Where the teeth are unevenly spaced, first place hidden points, then take the middle between the two.
3. The front holes should be right in front of the numbers.
NB: To annotate the arithmetic wheels. When a right wheel is driving its left wheel, on the right wheel it should read 9 on top before the transfer, and the other numbers should be written to the left.

That’s the whole information, survived up to the present for the Calculating Clock of Schickard. It seems the prototype of the machine, mentioned in the first letter, was rather successful, that’s why Schickard ordered the next copy for Kepler. It is unknown whether another copy was ever created, and how many devices are made or ordered by the inventor. It is out of the question, however, that such a device has not been delivered to Kepler. Most probably, only two machines were produced, the prototype, mentioned in the first letter, which was in the home of Schickard and disappeared after his death, and the second, made for Kepler, which was destroyed during the fire.

Let’s examine the structure and the functioning of the device. The Calculating Clock is composed of 3 main parts:

  • A multiplying device.
  • A mechanism for recording intermediate results.
  • A decimal 6-digit adding device.
A view to Napier's rods in the replica, created by Bruno v. Freytag Löringhoff (© Universität Tübingen)
A view of Napier’s rods in the replica (© Universität Tübingen)

The multiplying device is composed of 6 vertical cylinders with inscribed numbers of Napier’s rods (see the photo nearby).

From the front side, the cylinders are covered with 9 narrow plates with windows, which can be moved leftwards and rightwards. After entering the multiplicand by rotating the cylinders through the knobs on the upper side of the box, using the opening of the windows of plates can be made consecutive multiplying first by units of the multiplier, then by tens, and so on. The intermediate products can be added by adding devices.

The mechanism for the recording of intermediate results of calculations is composed of 6 rotating using small knobs disks with peripheries inscribed with digits, which can be seen in the small windows in the lower row (see the photo below). These disks are not connected to the calculating mechanism and don’t have a tens carry mechanism.

A view to the mechanism for recording of intermediate results of v. Freytag Löringhoff, (© Universität Tübingen)
A view to the mechanism for the recording of intermediate results (© Universität Tübingen)

The adding device is composed of six basic axes in a row. On each axis is mounted a smooth disk with ten openings (marked with 1 in the lower photo), a cylinder with inscribed digits (marked with 3), and a pinion wheel with 10 teeth (marked with 2), over which is a fixed pinion-wheel with 1 tooth (which are used for tens carry). On the other 5 axes are mounted pinion wheels with 10 teeth (marked with 4).

A view to the wheels mechanism of the Schickard's machine of v. Freytag Löringhoff (© Universität Tübingen)
A view of the wheel mechanism of the machine (© Universität Tübingen)

The smooth disks are used for entering the numbers and resetting the machine. The digits on the inscribed cylinders can be seen in the upper row of windows and are used for reading the results of adding and subtracting operations. Over each of the 10-teeth disks on the basic axes is mounted a one-tooth disk, in such a manner, that for each full revolution of the 10-teeth disk, 1-tooth disk enters once in contact with the proper intermediate disk and rotates it to 1/10 revolution. This is the mechanism of tens carry and it is not original. The use of an analog train of gear wheels (linked so that each time one wheel completes a revolution the next wheel turns one-tenth of a revolution, thus recording a carry) is very ancient and even appears in the works of Heron of Alexandria.

The axes can be rotated in both directions, so the machine can be used not only for addition but for direct subtraction too (no need to use the arithmetical operation complement to 9, as it was the case with Pascaline). Due to the intermediate disks, all smooth disks are rotated in the same direction.

The machine has also an indicator for overflow—a small bell, which rings if the leftmost pinion wheel rotates from 9 to 0.

Let’s make a simple multiplication with the machine, for example, 524 x 48. First, we have to rotate the rightmost cylinder to 4, the next cylinder to 2, and the third from right to 5 (the multiplicand is 524). Then we have to open the windows on the 8th row (units of the multiplier are 8) and we will see in the windows the first intermediate result (4192). We have to enter the 4192 in the calculating mechanism. Then we have to open the windows on the 4th (tens of multiplier are 4) row and to see the second intermediate result—20960, which we have to enter into the calculating mechanism, and we will have the result—25152.

As described by Schickard mechanism presented two eventual faults. First, the inventor didn’t describe a means for fixing the intermediate disks, which is certainly necessary. As you can see in the photos, the technicians of Mr. Freytag Löringhoff have provided such a mechanism (the small disks below the intermediate disks). The second problem is friction. At the beginning of the 17th century, the turret lathes had not been invented yet, so the pinion wheels had to be produced manually and with great precision, otherwise, the friction in case of full carrying (for example when to 999999 must be added 1) will be enormous and the machine will be hard for operating and easy to break. Schickard obviously had faced such problems, and that’s why his machine had only six main axes, despite the vital necessity of Kepler to work with big numbers for his astronomical calculations.

Biography of Wilhelm Schickard

Wilhelm Schickard was born in the morning at half past seven on 22 April 1592, in Herrenberg, Germany. Herrenberg is a small town, located in the area of Württemberg in the southern part of Germany, some 15 km from one of the oldest university centers in Europe—Tübingen, which University was founded in 1477.

Wilhelm was the first child in the family of Lukas Schickard (1560-1602), a carpenter and master builder from Herrenberg, who married in 1590 to Margarethe Gmelin-Schickard (1567-1634), a daughter of Wilhelm Gmelin (1541-1612), a Lutheran pastor from Gärtringen (a small town near Herrenberg) and Magdalena Rieger (1540-1580). Wilhelm had a younger brother—Lukas and a sister.

The Schickards is a well-known Herrenberg family, which was originally from the German region Siegerland (in region Nordrhein-Westfalen) but had moved south at the beginning of the 16th century. The great-grandfather of Wilhelm—Heinrich Schickard (1464-1540) from Siegen, called Heinrich Schickhardt der Ältere or Heinrich der Schnitzer, was a famous woodcarver and sculptor, whose wood-works (stalls from 1517) are still preserved in the church Stiftskirche Herrenberg. He was the founder of the Herrenberg’s Schickards family, moving in 1503 from Siegen, Siegerland, to Herrenberg. A brother of Lukas Schickard and uncle of Wilhelm is Heinrich Schickard (1558-1635)—one of the most prominent German architects of the Renaissance. The other uncle of Wilhelm is Philipp Schickard (1562-1635), a well-known in his lifetime theologian.

Wilhelm, a precocious child, started his education in 1599 in a Latin school in Herrenberg. After the death of his father Lukas in September 1602, his uncle Philipp, who served as a priest in Güglingen, took care of him, and in 1603 Wilhelm attended a Latin school there. In 1606 another uncle of his, Wilhelm Gmelin, took young Wilhelm to the church school in Bebenhausen Monastery, near Tübingen, where he was a teacher.

The school in Bebenhausen was associated with the Protestant theological seminary Tübinger Stift, in Tübingen, so in March 1607 the young Wilhelm entered a bachelor program of the Stift, held in Bebenhausen. In April 1609, he received his bachelor’s degree. In Bebenhausen Wilhelm studied not only languages and theology but also mathematics and astronomy.
In January 1610, Wilhelm went to the Tübinger Stift to study for his master’s degree.

Tübinger Stift nowadays
Tübinger Stift nowadays

Tübinger Stift is a hall of residence and teaching of the Protestant Church in Württemberg. It was founded in 1536 by Duke Ulrich for Württemberg born students, who want to be ministers or teachers. They receive a scholarship that consists of boarding, lodging, and further support (students receive for their personal needs six guilders per year cash). This was very important for Wilhelm because his family apparently was short of money and could not support him. After the death of his father in 1602, in 1605 his mother Margarethe married a second time to Bernhard Sick—a pastor in Mönsheim, who also died several years later, in 1609.
Besides Schickard, other famous students of Tübinger Stift are Nikodemus Frischlin (1547-1590), a famous humanist, mathematician, and astronomer from the 16th century; the great astronomer Johannes Kepler (1571-1630); the famous poet Friedrich Hölderlin (1770-1843); the great philosopher Georg Hegel (1770-1831) and others.

Stadtkirche St. Laurentius in Nürtingen, where Schickard served in 1614-1619
Stadtkirche St. Laurentius in Nürtingen, where Schickard served in 1614-1619

After receiving his master’s degree in July 1611, Wilhelm continued studying theology and Hebrew language in Tübingen until 1614, working at the same time as a private teacher of mathematics and oriental languages, and even worked some time as a vicarius in 1613. In September 1614 he took his last theological examination and started his church service as a Protestant deacon in Nürtingen, a town, located some 30 km northwest of Tübingen.
On 24 January, 1615, Wilhelm married to Sabine Mack from Kircheim. They were to have 9 children, but (as it was common in these times), only 4 survived by 1632: Ursula Margaretha (born 03.03.1618), Judith (b. 27.09.1620), Theophil (b. 3.11.1625) and Sabina (b. 1628).

Schickard served as a deacon till the summer of 1619. The church duties left him plenty of time for his studies. He continued his work on old languages, translations, and wrote several treatises, for example in 1615 he sent to Michael Maestlin an extensive manuscript on optics. During this time he developed also his artistic skills, creating several portraits, and astronomical tools, he had even a copper press.

In 1618 Schickard applied for and in August 1619, he was appointed as a professor of Hebrew language at the University of Tübingen, recommended by Herzog Friedrich of Württemberg. The young professor created his own method for presenting material, together with some wise auxiliary means, and taught also other ancient languages. Schickard learned also Arabic and Turkish. His Horolgium Hebraeum, a textbook for learning Hebrew in 24 hourly lessons, went through countless editions during the next 2 centuries. Actually, Schickard was a remarkable polyglot. Besides German, Latin, Arabic, Turkish, and some ancient languages like Hebrew, Aramaic, Chaldean, and Syriac, he knew also French, Dutch, etc.

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 the conjugation of Hebrew verbs by having two rotating discs laid on top of each other, the respective forms of conjugation appearing in the window. Besides Horologium Hebraeum, in 1627 he wrote another textbook—the Hebräischen Trichter, for German students of Hebrew. 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 center and apex of the cone. Schickard also made significant advances in map-making, writing a very important treatise in 1629, showing how to produce maps that were far more accurate than those that were currently available. His most famous work on cartography was Kurze Anweisung, wie künstliche Landtafeln auss rechtem Grund zu machen, published in 1629.

In 1631 Schickard was appointed professor of astronomy, mathematics, and geodesy at the University, because he had already significant achievements and publications in these areas, taking the chair from the famous German astronomer and mathematician Michael Maestlin, who died the same year. 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. As a 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 center of the universe, Schickard was a staunch supporter of the heliocentric system. In 1633 he was appointed dean of the philosophical faculty.

An important role in the life of Schickard played the great astronomer Johann Kepler. After their first meeting in the autumn of 1617 (Kepler was passing through Tübingen on his way to Leonberg, the Württemberg town where his mother had been accused of being a witch), they had a busy correspondence and several other meetings (in 1621 for a week, later on for 3 weeks). Kepler used not only Wilhelm’s talent for mechanics but also his artistic skills. In 1618 Schickard built a tool for comet watching for Kepler. Later on, Schickard took care of Kepler’s son—Ludwig, who was a student in Tübingen.

Schickard agreed also to draw and engrave the figures of the second part of the Epitome Astronomiae Copernicanae of Kepler 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. Schickard engraved also the figures for the last two books (the carving was done by one of his cousins).

A page from Kepler's <em>Harmonices Mundi Libri V</em>, with figures, made by hand of Schickard
A page from Kepler’s Harmonices Mundi Libri V, with figures, made by the hand of Schickard

Wilhelm also proposed to Kepler the development of a mechanical means of calculating ephemerides and created the first hand planetarium. Schickard created also, probably by request from Kepler, an original instrument for astronomy calculations (see the photos below). Kepler showed his gratitude, sending him several of his works, two of which are still preserved in the University Library in Tübingen.

A partial reconstruction of the Schickard's planetarium, Stadmuseum Tübingen (© Universität Tübingen)
A partial reconstruction of the Schickard’s planetarium (© Stadmuseum Tübingen)

In 1631 the life of Schickard and his family was under threat from the battles of the Thirty Years’ War, which approached Tübingen. Before the Battle of Tübingen in 1631, he fled with the entire family to Austria and returned after several weeks. In 1632 the family again fled to Austria. In June 1634, hoping for quieter times, he bought a new home in Tübingen, suitable for astronomical observations. His hopes were vain although. After the battle of Nördlingen in August 1634, the Catholic forces occupied Württemberg, bringing violence, famine, and plague with them. Schickard buried his most important notes and manuscripts, to save them from plunder. These partly survived, but Schickard’s family did not. In September 1634, in sacking Herrenberg, the soldiers from the Catholic forces beat Schickard’s mother—Margarethe, who died a lingering death of her wounds. In the next January of 1635 was killed by soldiers his uncle—the architect Heinrich Schickard.

At the end of 1634 died from plague Schickard’s eldest daughter—Ursula Margaretha, a girl of unusual intellectual attainment and promise. Then died his wife Sabine and the two youngest daughters—Judith and Sabina, two servants and a student, who lived in his house. Schickard survived this outbreak, but the following summer the plague returned, taking with it in September his sister, who was living in his house. Schickard and his only surviving child—9-year-old son Theophilus, fled to the village Dußlingen, near Tübingen, having the intention to emigrate to Geneva, Switzerland. However on 4 October 1635, fearing that his house and especially his library would be plundered, he returned to Tübingen. On 18 October he became sick of the plague and died on 23 October 1635. His little son followed him after a day.

Besides Kepler, Schickard also corresponded with some other famous scientists of his time—mathematician Ismael Boulliau (1605-1694), philosophers Pierre Gassendi (1592–1655) and Hugo Grotius (1583-1645), astronomers Johann Brengger, Nicolas-Claude de Peiresc (1580-1637) and John Bainbridge (1582-1643), and many others.

Wilhelm Schickard was one of the most reputable scientists in Germany of his time. The opinions of this universal genius from his contemporaries are—the best astronomer in Germany after Kepler’s death (Bernegger), the foremost Hebraist after the death of the elder Buxtorf (Grotius), one of the great geniuses of the century (Peiresc). However, like many other geniuses with wide interests, Schickard was in danger of stretching himself too thin. He succeeded in finishing only a small part of his projects and books, being struck down in his prime.

    Books, written by Wilhelm Schickard:

  • Cometenbeschreibung, Handschrift, 1619
  • Hebräisches Rad, 1621
  • Astroscopium, 1623
  • Horologium Hebraeum, 1623
  • Lichtkugel, 1624
  • Der Hebräische Trichter, 1627
  • Kurze Anweisung, wie künstliche Landtafeln aus rechtem Grund zu machen, 1629
  • Ephemeris Lunaris, 1631

Biography of Johann Pfister
Who was the mentioned in the second letter mechanic Joh. (Johann or Johannes) Pfister, who was involved not only in the production of Schickard’s calculating machines but also in other projects, for example in preparing metal plates for his and Kepler’s books?

The Pfister is a well-known for the time Tübinger family, known primarily as book-binders and Universitätspedells at the University of Tübingen (Universitätspedell was a relatively prominent position, responsible for arresting and detaining students in the karzer and functioning as a prosecutor at the university court).

A raft on the Neckar River in Tübingen, painting by Johannes Pfister from 1620
A raft on the Neckar River in Tübingen, painting by Johannes Pfister from 1620

First was Hans Pfister, the Older (1523-1607), the grandfather of Johannes Pfister, who was not only a member of Tübinger’s book-binders guild but served also a long time in the University of Tübingen as a watch and Universitätspedell.

Hans Pfister’s son—Hans (Conrad) Pfister, Jr. (b. 1560) succeeded his father and worked as a book-binder, seal-engraver, Universitätspedell, and schoolmaster in Tübingen. He married in 1578 Anna Ruckaberle (1563-1624), the family had ten children, and one of them was Johannes Pfister.

Johann(es) Pfister was born on 15 January 1582, in Tübingen. He succeeded in the family trade and worked as a bookbinder and printer, as well as an engraver and mechanic. He must have been a decent painter also because an interesting painting from 1620 survived to our time (see the upper painting of Pfister). Pfister married in 1606 to Rosina Steininger, a daughter of the Lutheran scholar Gall Steininger.