Idearum Operatricium Idea sive Hypotyposis et detectio illius occultae Virtutis, quae Semina faecundat, & ex iisdem Corpora organica producit. by MARCI A KRONLAND, Johannes Marcus

Finely engraved title-page & many unusual engravings in the text (some full-page). [350] pp. (of 352, lacking as usual a leaf of the table of contents A4, see below). 4to, cont. vellum over boards, yapp edges, sides stamped in gilt with a central arabesque device on each cover, flat spine decorated, edges gilt & gauffered. [Prague: Typis Seminarii Archiepiscopalis], 1635. [bound with]:-- . De Proportione Motus seu Regula sphygmica ad celeritatem et tarditatem pulsuum ex illius motu ponderibus geometricis librato absque errore metiendam. Finely engraved title, engraved port. of the author on verso, one engraved plate, & 31 engraved illus. in the text. Each page of text printed within a border of printer's ornaments. 64 leaves. 4to. [Prague: J. Bilina, 1639]. [bound with]:-- . De Proportione Motus Figurarum Recti Linearum et Circuli Quadratura ex Motu. Finely engraved title, & 32 engraved illus. in the text. Each page of text printed within a border of printer's ornaments. 71 (of 72) leaves. 4to. Prague: [ex Typographia Academica], 1648. [bound with]:-- . Thaumantias Liber De Arcu Coelesti deque Colorum apparentium Natura, Ortu, & Causis. Finely engraved illus. title & numerous engravings in the text. 3 p.l. (of 4, lacking the engraved port.), 268, [2] pp. 4to. [Prague: Typis Academicis, 1648]. A magnificent sammelband, containing Marci's four most important books. I. First edition of the author's very rare first book; Marci (1595-1667), professor of medicine at Prague University has been called the "Bohemian Galileo." Needham, in his History of Embryology, describes Marci's theories regarding embryology in the present book as a "development of extraordinary interest" (p. 80). "His Idearum Operatricium Idea, published in 1635, was a mixture of purely scientific contributions to optics, and speculative theories about embryology. Thus he explained the production of manifold complexity from the seed in generation by an analogy with lenses, which will produce complicated beams from a simple light-source. The formative force radiates from the geometrical centre of the foetal body, creating complexity but losing nothing of its own power... "Marcus Marci thus links together the following trends of thought: (1) the old Aristotelian theory of seed and blood, (2) the new rationalistic mathematical attitude to generation as e.g. in Gassendi and Descartes, (3) the new experimental approach, in his contributions to optics, (4) the cabbalistic mysticism of light as the fountain and origin of things. Finally (5) by his brilliant guess of centres of radiant energy, he anticipates much of modern embryology (field theories, fate of part as function of positions, etc.). Pagel and Baumann give an elaborate discussion of his opinions."-Needham, pp. 80-81. As stated above this copy lacks the second leaf of the table of contents. This was usually excised by the printer or binder as the contents listed on this leaf were not printed in the present book due to a change of plans. II. First edition, and very rare, of the best known and most important book of Marci. The present book contains "his theory of the collision of bodies (particularly elastic bodies) and gave an account of the experiments whereby he reached it. Although these experiments are described precisely, Marci was unable to formulate general quantitative laws from them, since his results were not drawn from exact measurements of either of the sizes and weights of the spheres that he employed or of the direction and velocity of their motion. Rather, he was content with simple comparisons of the properties that he investigated, characterizing them as being 'smaller,' 'bigger,' or 'the same' as each other...despite these shortcomings, his observations and conclusions are generally right. He was able to distinguish different qualities of spheres and to state the concepts of solid bodies and of quantity of motion."-D.S.B., IX., p. 97. The delightfully engraved title-page illustrates many of the experiments described in the book: weights being dropped from a high tower, a cannon being fired, careening balls on a billiard table, sparks flying off a grinding wheel (centrifugal force), a man swinging from two ropes (pendulum motion), and a man batting a ball against a wall. Marci "was the first to make substantial progress with the difficult problem of impact, a problem that Galileo touched on without success and that Descartes completely muffed."-E.C. Watson in American Journal of Physics, Vol. 16 (1948), pp. 246-47. III. First edition of what I believe to be the rarest of all the books by Marci. The present book, concerned with the theory of collisions, is a continuation and elaboration of his 1639 publication De Proportione Motus seu Regula Sphygmica. In this work, Marci responds to criticisms made of his 1639 book [see item II] and presents new theories concerning the geometrical form of bodies in movement, the properties of free fall, the duration of the oscillation of a pendulum and its length, etc. There are a number of references to Galileo. Lacking the fourth preliminary leaf (with engraved portrait of the author on verso). IV. First edition of a very rare book. "Marci also carried out research in optics, setting down most of his results in Thaumantias...(1648). In his optical experiments, designed to explain the phenomenon of the rainbow, Marci placed himself in the line of such Bohemian and Moravian investigators as Kepler, Christophe Scheiner, Baltasar Konrad, and Melchior Hanel. In his experiments on the decomposition of white light, for which he employed prisms, Marci described the spectral colors and recorded that each color corresponded to a specific refraction angle. He also stated that the color of a ray is constant when it is again refracted throughout another prism...He did not mention the reconstitution of the spectrum into white light (a result that is first to be found in the work of Newton), although he did study the 'mixture' of colored rays. He also made inconclusive experiments on light phenomena on thin films."-D.S.B., IX, p. 97. Lacks the portrait of Marci. Minor browning but a very fine sammelband; it is hard to imagine a more pleasing object. Bookplate of Wolfgang Engelbert, Graf von Auersperg. Ex Bibliotheca Mechanica. ❧ D.S.B., IX, pp. 96-98. Roberts & Trent, Bibliotheca Mechanica, pp. 214-15. IV. Boyer, The Rainbow, pp. 219-(& see pp. 219-25 for a long discussion of this book)-"Of considerable significance for the attempt to explain color quantitatively." .