March 8, 1877] 



NA TURE 



409 



instruments and iheir uses, and also of His chemical 

 labours. This work also contains views and plans of his 

 observatory at Huen, and in the British Museum is an 

 original copy presented by Tycho to his friend, Dr. 

 Thaddejs Haggecius ab Hayek, Chief Physician to the 



../. c 



{:7^//f?^^ ff Q Q . 



— >' 

 > 



1 



Kingdom of Bohemia, and bearing the fihe autograph 

 which we here reproduce (one-half the size of the 

 original). The work was printed at Wandesburg in 

 1598, and a copy, along with a MS. catalogue of i,ooo 



ARMILLiE ZODIACALES. 



Ecliptic Astrolabe (Tjcho Biahe) similar to that used by Hipparchus. 



stars, was sent to the Emperor Rudolph II., a great 

 lover of alchemy and astronomy. The result was an in- 

 vitation to Tycho to go to Prague, with an assurance 

 that he would receive the warmest welcome. Thither he 

 went with his family in 1599, and most of his fine set of 



instruments followed soon afcer. An annual pension of 

 3,000 crowns was bestowed upon him, and the castle of 

 Benach given him for residence, though in the beginning 

 of 1601 he removed into Prague, to the house of his late 

 friend Curlius, which the Emperor had purchased and 

 presented to the astronomer. It was at this period that 

 Kepler, then about twenty-nine years of age, lived and 

 worked with Tycho, who procured for him the post ot 

 imperial mathematician, for which, however, Kepler never 

 seems to have reteived any income. 



Notwithstanding the munificent treatment of Rudolph, 

 Tycho's misfortunes in Denmark must have told seriously 

 on his health, and his end was near. He had a serious 

 attack on October 13, which so told on his weakened con- 

 stitution, that although the immediate cause was re- 

 moved, his strength failed him, and he expired on the 



QVADRANS MAXIM FS CHALI 



BEUS QJUABRATO IVCLUSUS, ET 



Horizonti Azimuchali chalybeo 

 infu^ens. 



All-azimuth of Tycho Brahd. 



24th of the same month, within two months of completing 

 his fifty-fifth year. 



As to Tycho Brahd's work, we cannot do better than 

 give the following summary by Sir David Brewster : — 



"As a practical astronomer, Tycho has not been sur- 

 passed by any observer of ancient or of modern times. 

 The splendour and number of his instruments, the inge- 

 nuity which he exhibited in inventing new ones and in 

 improving and adding to those which were formerly 

 known, and his skill and assiduity as an observer, have 

 given a character to his labours, and a value to his obser- 

 vations, which will be appreciated to the latest posterity. 

 The appearance of the new star in 1572 led him to form 

 a catalogue of "]"]"] stars, vastly superior in accuracy to 

 those of Hipparchus and Ulugh Beig. His improvements 

 on the lunar theory were still more valuable. He dis- 

 covered the important inequality called the variation, and 

 likewise the annual inequaUty which depends on the 

 position of the earth in its orbit. He discovered, also, 



