The "Material Sphere", 1558, 1559 The first of these,
De Sphaerae Materialis Fabrica et Usu 128 Canonum Tituli ("128 Precept Titles on the Construction and Use of the Material Sphere"), produced by Iohannes Bathenius at Cologne in 1558, styles the author as
Doctor of both laws ("utriusque Iuris D."), Poeta laureatus, and Mathematicus. It is a 24-page list of the chapter-headings of a projected work in eight books or sections, and is dedicated to his three students Jerome de Corde of
Tournai, Gaspar Spoetz of
Antwerp, and Henry Middelburgh of
Brussels, making acknowledgement of the work of several contemporaries including Gemma Frisius. This, then, is the "Material Sphere". In his dedication to Hufkens of
Groningen, which opens with a detailed account of his travels, he cites as his principal authority the work of
Johannes de Sacrobosco, in particular the
Tractatus de Sphaera Mundi (written about A.D. 1230 and describing a
Ptolemaic cosmography). Taisnier's work, of 46 folios, restricts itself to the astronomical uses of the instrument, though introducing an astrological theme in the dedication, and closing with the promise of an expanded work on the uses, yet to come. The intention is to describe the improvement of the
armillary sphere by certain corrections, and by the addition of rings to make the instrument more useful in its application to astronomy, physiognomy and cheiromancy.
Judicial Astrology, 1559 A more substantial astrological work, of nearly 200 folios, Taisnier's
Astrologiae Iudiciariae Ysagogica, et Totius Divinatricis Artis Encomia ("Introductory Contextual Study of
Judicial Astrology, and the Encomia of the Whole Divinatory Art"), appeared also in 1559, produced at Cologne by Arnold Birckmann. This book bore an august dedication, to
William, Duke of Jülich-Cleves-Berg,
Count de la Marck,
Count of Ravensberg and Lord of Ravenstein (1516-1592), whose servant Taisnier declares himself to be. The Dedicatory Letter is important for the author's lengthy exposition of the four "Mathematical quantities", namely Astronomy, Geometry, Arithmetic and Music, "which are so interrelated that any one of them remains imperfect without the other." This résumé (which, according to Bosmans, may embody text first presented in separate form as
Tabula Universalis Most valuable, perhaps, is his summary of a projected or completed treatise on Music (not surviving in manuscript or print among his known works), which both in its terminology of musical theory and its description of instruments, should have held exceptional interest. His observations on
Musica Reservata have attracted particular attention.
The Spherical Rings (new edition), 1560 In 1560 a new edition of his work on the use of the Spherical Rings,
De Annuli Sphaerici Fabrica et Usu Libri Tres Geometrici, was revised from the 1550 Palermo edition. This contribution to the Geometrical part of his scheme came from the press of Johannes Ricardus at Antwerp. The illustrations from the earlier edition, many dated 1549, were re-used, and the text was arranged in three sections: the first concerned the measurement of heights and distances of structures: the second described the measurement of the hours of the day by observation of the sidereal
hour angle; the third concerned angles of trajectory for bombardment by artillery, and measurements for the construction of ladders and temporary assault bridges.
The Cheiromancy ("Opus Mathematicum"), 1562 1562 saw the publication of his great
cheiromantic endeavour,
Opus Mathematicum octo libros complectens. An astrological work, six of the eight sections are devoted to the interpretation of the lines and aspects of the palm for divination and prognostications; the seventh section concerns physiognomy, and the eighth reproduces the
Astrologiae Iudiciariae Ysagogica and
Encomia. The sixth section, pp. 387-449, contains 61 extended palm-readings in which Taisnier tells us much about his own life from the 1530s onwards. The whole work was produced at Cologne by Johannes Birckmann and Werner Richwine, and Taisnier dedicated it to
Johann Jakob Fugger (1516-1575), a very prominent patron of arts and sciences. The woodcut author-portrait of Taisnier dated 1562 appears near the beginning of the book. A second or reprinted edition was produced at Cologne by Theodor Baumius in 1583. In the
Opus Mathematicum, uniquely, Taisnier claimed to have travelled in America:"Potiorem aetatis meae partem LIII. annos nunc natus, in diversis studiorum generibus versatus, totam fere Europam, magnam Africae, Asiae, Ameriaeque partem perlustravi, expertissimorum virorum ubique varias in diversis facultatibus opiniones colligens, collectas (ut par erat) in publicis Scholis et Academijs auditoribus communicavi, praesertim Romae, Ferrariae, Venetijs, Paduae, Florentiae, Panhormi, publice legendi provinciam suscipiendi..."
(For the better part of the 53 years that I have now lived, being well versed in various kinds of studies, I have travelled studiously through nearly the whole of Europe, and a great part of Africa, Asia and America, everywhere collecting the various opinions of the most experienced men in their diverse fields of expertise: these things I have communicated (in like fashion) to audiences in the public schools and academies, especially by undertaking public reading at Rome, Ferrara, Venice, Padua, Florence, and Palermo...) Taisnier's cheiromancy was strongly astrological in method. It was of this work that
Giacomo Filippo Tomasini wrote, in 1630, that it contained such a mass of information that it merely wore out the patience of those whom it was intended to enlighten. Tomasini illustrated Taisnier's symbol as a medallion showing a right hand upright with the Great Triangle marked in the palm, and the words "
In Manibus Sortes Ejus" above. It is clear that in his cheiromantic and physiognomic works, Taisnier owed a considerable debt to the works of
Bartolomeo della Rocca (1467-1504), also called Barthélemy Cocles, whose
Chyromantie ac Physionomie Anastasis, cum approbatione magistri Alexandri Achillinis was published at Bologna in 1504, but more probably known to Taisnier from the
Physiognomiae et Chiromantiae Compendium produced by Iohannes Albertus at Strasbourg ("Argentorati") in 1536. Thorndike observed that the project of combining cheiromancy, physiognomy and astrology in a single work was presumably suggested by the example of
Johannes ab Indagine (1467-1537). is a celebrated work of plagiarism. In his dedication to Jan Gebhardus, Taisnier claims the authorship as "hoc meum parvulum opusculum" -
this my little work. Yet the text on the nature of the magnet is closely adapted from the
Epistola de magnete of
Peter of Maricourt (floruit 1269), while that on perpetual motion was actually by a living author, a
Treatise on the fall of bodies of 1554 by
Gianbattista Benedetti (1530-1590). Neither author is acknowledged, but the 1562 author-portrait of Taisnier reappears. File:Jan Taisnier. Line engraving by N. de Larmessin, 1682. Wellcome V0005718.jpg|thumb|right|200px|Portrait of Taisnier by N. de Larmessin, 1682, Benedetti himself drew attention to Taisnier's theft of his work, in the Preface
Ad Lectorem of his
De Gnomonum Umbrarumque Solarium Usu Liber (Turin 1574). In a long and extremely scathing condemnation, he cast doubts on Taisnier's claims to authority in anything he wrote. He speaks of those who criticize others while stealing their work, "...ut fecit impurissimus omnium Iohannes Taisnerus Hannonius. Qui opusculum nostrum... ita integrum sibi desumpsit, ut nihil praeter authoris nomen immutaverit; quid enim mutavisset, qui nec percipere poterat quae in ea disputatione continerentur? Homo vanus ab omni mathematica facultate alienus, qui merito propter crassissimam ignorantiam verebatur, ne vel aliqua Syllaba sublata aut addita totius tractationis inficeretur substantia. Credidit (ut opinor) me iam vita functum qui furti nunquam argui posse confidit..."
("as John Taisnier Hannonius did, the most unwholesome of all of them. Who so completely took for himself our little work, that he altered nothing except the name of the author - for what could he have changed, this vain man devoid of all mathematical capability, who was not able to grasp the things contained in that discourse? who justly feared, on account of his very gross ignorance, that by the addition or removal of a single syllable he might undo the meaning of the entire argument. I think he believed that I was already dead, and trusted that I would never be able to denounce his theft...") That (and much more) having been said, Bosmans makes the case that Taisnier, as a teacher, was attempting to synthesize and disseminate knowledge for students and for practical uses. He observes that it was not unusual in Taisnier's time for authors to make use of existing texts without specific acknowledgement, and that a particular degree of hostility seems to have been directed towards him by later commentators. On the other hand Bosmans acknowledges that, in his letters of dedication and frequent recitation of his credentials, Taisnier showed a discomforting tendency towards self-promotion, and joins the chorus of regret that Taisnier did not leave a musical treatise worthy of his undoubted expertise in that field. The woodcut of 1562 formed the model for a fresh engraving by Nicholas de Larmessin for this publication. ==Epitaph==