444 



K E P L E 



Kepler, of Tycho, however, in 1601. put an end to those feel- 

 "- I* ings of discontent, which might soon have ripened into 

 a serious quarro'. 



The mind of Kepler was deeply tin-red with the er- 

 rors of astrology. Jn 1602, he published at Prague, 

 Jlis A- .- ni^i-rfiilinncn/a ds- finidtim.-nlix Astroloyia; 

 certioribus . <nl cowo'heuriam spectans, in which he speaks 

 of the possibility of predicting future events by the as- 

 pects of the planets. And in another work on the same 

 subject, which appeared at Frankfort in IfcilO, entitled 

 Tcrliuia liilervcnirns, he exhorts theologians, physi- 

 cians, and philosophers, but principally Philip Feselius, 

 to take care that they do not injure their own interests, 

 by rejecting the errors of astrology ; and he attempts 

 to shew, that an influence may be communicated from 

 the planets to the earth, through the medium of the 

 light which they reflect. 



In 1 604, he published at Frankfort, his Paralipome- 

 na ail Vililloiicm, quibiix Aslrontmiae pars Optica tradi- 

 tur, po/issimum de artijici:>sn observation el eslimalione 

 diamelrorum, ddiqitinriimque Soils el Luna;. This work 

 contains the method of calculating eclipses, which is in 

 use at the present day. In 1605, he published at 

 Prague, his Epistola ad rerum celestiiim amafore* uni- 

 versos, respecting the eclipse in the month of October 

 1605 ; which was followed in the same year, by his 

 l.pixlola de Comet a 1604, SfC. which was the prelude to 

 his great work on the star in the foot of Serpentarius. In 

 1606, tie printed at Frankfort, his Sylva C/ironologica ; 

 and in the same year, appeared his work, entitled, De 

 Stella Novo in pede Serpentarii el qui sub fjiis exortum 

 de novo iniit Irigono igneo, Libellus Astronomicis, Physicis 

 Metaphysicis, et Astral gicis dispulationibus etidoxis et 

 paradoxis plenus. In 1608, Kepler published at Halle, 

 a history of the new comet of 1607, with a discourse on 

 the nature and motion of comets, and their indications. 

 In looking at the sun in a camera obscura, he maintain- 

 ed that he had seen Mercury on the sun's disc. He 

 published the same error at Leipsic, in 1609, in a pam- 

 phlet entitled, Phenomenon singitlnre, sen Mercurius in 

 Sole ; but in his Ephemerides for l6l6, he acknowledges 

 his mistake, and congratulates himself on having been 

 the first that observed the spots of the sun. His fa- 

 mous work, entitled Aslronomia nova amo^oynres, five 

 Physica ccelestis Iradita commenlariis de motibus stellce 

 Martis ex observalionibus Tychonis Brake, appeared at 

 Prague in 1609. This work, as we have already shewn, 

 (see our article ASTRONOMY, Vol. II. p. 596,) conducted 

 its author to the great discovery of the true form of the 

 planetary orbits. In 1611, appeared his Disserlatio 

 cum Nuticio Sidereo nuper ad mortalcs misso a Galileo, 

 in which he announces to Galileo, the great satisfaction 

 which his discoveries had given him. He expresses his 

 hope, that he may discover other satellites round Saturn 

 and Mars. He states his astonishment, that telescopes 

 had not been made formerly, particularly after what 

 Baptista Porta had said of them in his Magia Naturalis ; 

 and, in addition to many interesting observations, he 

 conjectures that Jupiter had a motion of rotation about 

 his axis. 



In 1 611, he published at Augsburg, his Dioptrical ; 

 item examen praef'ationis Jo PENAE Galliin Optica Eucli- 

 dis ; De ttsu Optices en PIMosoplna. This work was 

 reprinted at London, in 1653. Descartes is said to 

 have borrowed freely from it. When Descartes was 

 charged with this, he acknowledged that Kepler was 

 his first master in optics, and that he understood more 

 of the subject than all hia predecessors. In the same 



year appeared his Slrena, scu de Nive scratifftila, in 

 which he seems to have bee the first that discovered 

 the tendency of water to crystallize in angle's of Co . 



In 1()15, Kepler published his Eclogdf-chronica; ex 

 tpitilolis doclissimonim nlitjuol rirnnim ct suis muluis ; 

 and in the same year at Lintz, his Nova Slereomclrin do- 

 liorum mnariorum, which he. is said to have composed, 

 in consequence of a revenue officer having made a false 

 measurement of his wine at the time of his marriage. 

 His Rpkemeridef Nnvce Mot. Celest. ab anno 16'1~, ap- 

 peared at Lintz in 1617. 



On the 15th May 1618, Kepler has left it on record, 

 that he discovered the beautiful relation between the 

 squares of the periodic times and the cubes of the distan- 

 ces of the planets. Inthesameyear.hepublishedatLintz, 

 his Epitome Astronomies Copernicance in sc-ptem liliriscon- 

 scripla. This work contained only the three first books ; 

 the fourth appeared in 1622, and the three last in 16'21. 

 In 1619, he published at Lintz his Harmonicrs Mundi 

 libri quinque, geometricits, architectonicus, harmonicus, 

 psychologies, astronomicus, cum appendice continent mi/s- 

 terium cosmographicum ; also his treatise De Cornells Li- 

 belli Ires astronomicus, physicus, astrologicits. Ejusdem 

 Cometarum phytiologia nova et paradoios ; and another 

 work entitled Prngnoslicon, SfC. or the Prediction of Mis- 

 fortunes jor Governments and Churches, principallyfrom 

 the Comet and the Earthquake in 1618 ard 1019. The 

 first of these works, viz. the Harmonica, is dedicated to 

 James VI. of Scotland. Kepler attempts to shew, that 

 there is a resemblance between the distances of the hea- 

 venly bodies, as seen from the sun in their aphelia and 

 perihelia, and the division of the musical octave ; but 

 though this part of his book is in every respect absurd, 

 yet he appears from this work to have studied music as 

 a science, and also to have been practically acquainted 

 with it. The discovery of the four satellites of Jupi- 

 ter, seems to have first pointed out to him the error 

 which he had committed. 



In 1624, appeared at Marpurg, his Chilias Logarithm 

 moriim, to which a supplement was added in 1625, when 

 he also published his Hypera^piftes, ffc. quo libra doclri- 

 na prestantissima de parallaxibns, deque novorum siderum 

 in sublima adhere discurs'wnibiis rcpetifur ct confirmalur. 



After the death of Tycho, the emperor Iiodolph com- 

 manded Kepler to complete the astronomical tables 

 which had been begun by his friend ; but he was not 

 able to bring his labours to a termination till the year 

 1627, when they at last appeared at Ulm, under the 

 title, Tabula; RudolphincE, quibus astronomicce scienticE, 

 temporum louginquitate collapsce, restauralio continetur, a 

 Tychone Bra/ie primum animo concept a el dcstinata anno 

 C/ir. 1564, exindeobservationibus siderum accuratissimiis 

 post annum pr<ecipue 1572, serio affeclata, tandem tra- 

 ducla in Germanium, inque Aulam et nomen Rodolphi 

 imp.' anno 1598. The delay in the publication of this 

 work, arose from the difficulties which Kepler experi- 

 enced in obtaining the pecuniary means which were 

 necessary for carrying it on. The emperor Rodolph 

 had given orders in 1609, that, besides the expence of 

 the edition, the arrears of his pension, amounting to 

 2000 crowns, and also 2000 crowns more, should be 

 paid ; yet it was not till two years after that these orders 

 were executed. Under the emperors Matthias and Fer- 

 dinand, he experienced the same difficulties ; but after 

 the .year 1621, Ferdinand paid all his arrears, and all 

 the expences necessary for completing the work. 



As soon as these tables were completed, Kepler solici- 

 ted, and obtained the emperor's leave, to take up his re- 



Kepler. 



