NA TURE 



[November- 7, 1901' 



observed by him had at most a very small parallax he 

 proved that they were celestial bodies and not mere 

 phenomena in the earth s atmosphere. Important as 

 this discovery was, it is quite eclipsed by the splendour 

 of Tycho's discoveries with regard to the motion of the 

 moon. The ancients knew that the moon's orbit forms 

 an angle of about •,' with the ecliptic, that the two points 

 of intersection (the nodes) travel round the ecliptic in the 

 direction from east to west in about nineteen years, also 

 hat the earth is not at the centre of the lunar orbit, and 

 hat the line of apsides completes a revolution ("from west 

 to east) in less than nine years. The great perturbation 

 in longitude now known as the evection, by which the 

 place of the moon may be put forward or backward as 

 much as \ l6'. was also known, having been dimly per- 

 ceived by Hipparchus and clearly demonstrated by 

 Ptolemy. But since his time no advance had been made 

 (Sedillot's assertion that Abul Wcfa discovered the varia- 

 tion has been clearly and finally disproved). The accurate 

 and long-continued observations ofTycho Brahe revealed 

 the existence of another inequality in longitude, known 

 as the variation, which affects the place of the moon to 

 the extent of 40', by which amount the moon is ahead of 

 her mean place about three and a half days after new and 

 full moon, and as much behind it about three and a half 

 days after the first and last quarters. He also found the 

 annual equation or the lengthening of the moon's period 

 of revolution in winter and its shortening in summer. 

 Finally, Tycho discovered the variation of the inclination 

 of the lunar orbit and the irregularity of the motion of 

 the nodes. After this series of brilliant successes he 

 cannot have doubted that his observations were destined 

 to reveal the mysteries of planetary motion, and already 

 in 1 59 1 he had commenced to suspect the existence of 

 unknown complications in the motion of Mars, which he 

 afterwards alluded to m a letter to Kepler in 1 598, in which 

 he stated that the epicycle of Mars appeared to vaiy in 

 size. Preparations had already been made for com- 

 mencirig the discussion of the observations of the planets, 

 when an early death closed the life-work of Tycho and 

 obliged him to leave the completion of it to Kepler. 



The 300th anniversary of Tycho Brahe's death has 

 been celebrated in his native land by a festive meeting of 

 the .Academy of Science at which the venerable King 

 Christian was present, and at which orations were de- 

 livered setting forth the 'importance of Tycho's scientific 

 work. At Prague, where he died, the monument or\-er his 

 ■recently restored tomb in the Teyn Church was again un- 

 veiled, and the interest which the citi?ens of Prague have 

 always shown in the illustrious exile was manifested in 

 various ways. P/ut though Tycho towards the end of his 

 life felt himself r>egleoted in Denmark and left the country 

 in order to enjoy the society of learned and congenial 

 minds elsewhere, :he never forgot the land of his ancestors 

 and his birth, and on the titles of his last writings, 

 as on his first, he describes himself as "Tycho Brahe 

 Danus." 



The Copenhagen Academy has chosen a very fitting 

 way of doing honour to the memory of the greatest 

 ■scientific man Denmark has produced by publishing a 

 facsimile reprint of his earliest publication, 'M')e nova 

 Stella" 11573). Tycho's four principal works are found 

 in all great libraries and are not unfrequently met 

 with in the lists of second-hand booksellers. lUit the 

 bookonthesplendid new star which appeared in Cassiopeia 

 in Noveml)er 1572 is so extremely scarce that not a single 

 historian of astronomy had ever seen it or even been able 

 to give the title correctly until the writer of these lines 

 gave an account of it in 1890. Tycho says himself that 

 not many copies were printed and only n few were sent 

 abroad, for which reason he afterwards reprinted the 

 more important parts of it in his larger work, " Astronomijc 

 Instaurata: Progymnasmata," on which he was engaged 

 during the last fourteen years of his life and which was 



NO. •I&yi, VOL. 65] 



published after his death. But the whole ofthe original' 

 book, as It left the hand ofthe young author, is of great 

 historical interest, and we are glad to see the fine reprint 

 now issued, as the star of 1572 was so intimately connected' 

 with the progress of Tycho's work. 



In a short I.atin preface and a Danish postscript of 

 thirty pages, M. Pechule, of the Copenhagen Observa- 

 tory, has given a short summary of the origin and 

 contents of the book. Tycho's manuscript was an astro- 

 nomical, astrological and meteorological almanac for the 

 year 1573, in which he, after a lengthy introduction (to 

 the almanac proper), had inserted his essay on the new 

 star, another on the lunar eclipse of December 1573 and 

 a poem to Urania. After a good deal of persuasion by 

 several friends, Tycho allowed the book to be printed in 

 the spring of 1573, omitting, however, the main part of 

 the almanac. It contains 53 ff, and has now been 

 exactly reproduced in facsimile, but it has been collated 

 with a M.S. copy partly written in Tycho's own hand and 

 preserved in the Imperial library at Vienna, in which 

 way a few corrigenda were noticed which are gi\en at the 

 end of the reprint. The book, which is beautifully got 

 up, also contains a specimen of Tycho's handwriting and 

 a copy of a very fine jjortrait, drawn with pen and ink, 

 found in the Royal collection of engravings at Copen- 

 hagen and by some ascribed to the Dutch engraver 

 Goltzius, by others to the painter Gemperlin of Augsburg, 

 who came to Denmark with Tycho in 1575 and after- 

 wards painted the well-known portrait on his mural' 

 quadrant. To anyone acquainted with the contemporary 

 literature on the new star- and on comets this book will' 

 be of great interest, as it gives a very sober account of 

 the startling celestial phenomenon which had given rise 

 to a host of more or less worthless pamphlets and books, 

 and shows that the want of parallax and motion proves 

 the star to belong to the region of the fixed stars. \X. 

 the same time, it is interesting to see that the author, 

 who was destined afterwards to give the deathblow to- 

 the -Atistotelean idea ofthe atmospheric origin of comets, 

 was still a believer in this doctrine when he wrote his 

 first book, but also that he was already then thoroughly 

 aware that the great desideratum of astronomy was an 

 •extensive series of observations which he hoped to be 

 able to supply if health permitted and the necessary 

 means were granted him. 



Scania, the province east of the Sound, where Tycho- 

 was born, and the little island of Hveen, on which his 

 observatory stood, formed parts of the kingdom of Den- 

 mark from before the dawn of history and till 165S, when 

 they were torn fronji the country which had not sufficiently 

 valued him and incorporated in Sweden. It is therefore 

 natural that the recent anniversary of his death also 

 attracted attention in Sweden, and in honour of the day 

 the Physiographic Society of Lund has published a. 

 Fcstskrijt (20 pp., 4io., with three plates), in which Prof. 

 Charlier, of Lund, gives an account ofthe recent explora- 

 tion of the scanty remains of Tycho's buildings on the 

 island. The foundations of L'raniburg were laid bare, as- 

 also the floors of the half-subterranean observatory (Slel- 

 hvburgum (Stjerneborg)i but scarcely anything was found 

 more than what the clergyman Ekdahl unearthed in 

 1823. It has repeatedly, in 1823, in 1868 after the ex- 

 amination ofthe site by d .■\rrest, and now again on the 

 present occasion, been pointed out that " something 

 ought to be done ' to protect the ruins from wind and 

 weather, and we may add from relic hunters also. If 

 this was desirable formerly, when Hveen was a lonely 

 place to which nobody ever went, iti has Isecome infinitely 

 more important now, as the island seems to have become- 

 the common resort of Sunday trippers from both shores- 

 of the .Sound, and it would certainly be safer to cover up- 

 the foundations again than to leave them unprotected. 

 Jt has recently been suggested that the observatory 

 might easily be rebuilt from Tychoii detailed and 



