268 HISTOKY OF FORMAL ASTRONOMY. 



though a writer of credit in other respects, had spoken very childishly 

 in that matter. In another epistle prefixed to the work (by Andreas 

 Osiander), the reader is reminded that the hypotheses of astronomers 

 are not necessarily asserted to be true, by those who propose them, 

 but only to be a way of representing facts. We may observe that, in the 

 time of Copernicus, when the motion of the earth had not been connected 

 with the physical laws of matter and motion, it could not be consid- 

 ered so distinctly real as it necessarily was held to be in after times. 



The delay of the publication of Copernicus's work brought it to the 

 end of his life; he died in the year 1543, in which it was published. 

 It was entitled De Revolutionibus Orbium Coelestium Libri VI. He 

 received the only copy he ever saw on the day of his death, and never 

 opened it: he had then, says Gassendi, his biographer, other cares. 

 His system was, however, to a certain extent, promulgated, and his 

 fame diffused before that time. Cardinal Schomberg, in his letter of 

 1536, which has been already mentioned, says, " Some years ago, when 

 I heard tidings of your merit by the constant report of all persons, my 

 affection for you was augmented, and I congratulated the men of our 

 time, among whom you flourish in so much honor. For I had under- 

 stood that you were not only acquainted with the discoveries of ancient 

 mathematicians, but also had formed a new system of the world, in 

 which you teach that the Earth moves, the Sun occupies the lowest, 

 and consequently, the middle place, the sphere of the fixed stars re- 

 mains immovable and fixed, and the Moon, along with the elements 

 included in her sphere, placed between the orbits (caelum) of Mars and 

 Venus, travels round the sun in a yearly revolution." 8 The writer goes 

 on to say that he has heard that Copernicus has written a book ( Com- 

 mentarios), in which this system is applied to the construction of Tables 

 of the Planetary Motions (erraticarum stellarum). He then proceeds 

 to entreat him earnestly to publish his lucubrations. 



8 This passage has so important a place in the history, that I will give it in the 

 original: — " Intellexeram te non rnodo veterum mathematicorum inventa egregie 

 callere sed etiam novam mundi rationem constituisse : Qua doceas terram moveri: 

 solem imum mundi, atque medium locum obtinere : coelum octavum immotum 

 atque fixum pexpetuo manere: Lnnam se una cum inclusis suae spherse elementis, 

 inter Martis et Veneris ccelum sitam, anniversario cursu circum solem convertere. 

 Atque de hac tota astronomiae ratione commentaries a te confectos esse, ac errati- 

 carum stellarum motus calculis subductos tabulis te contulisse, maxima omnium 

 cum admiratione. Quamobrem vir doctissime, nisi tibi molestus sum, te etiam 

 atque etiam oro vehementer ut hoc tuum inventum studiosis communices, et tuas 

 de mundi sphcera lucubrationes, una cum Tabulis et si quid habes prseterea quod 

 ad eandem rem pertineat primo quoque tempore ad me mittas." 



