$ xos no] Tycho's Last Years 141 



the short remainder of Tycho's life. Though he was 

 by no means an old man, there were some indications 

 that his health was failing, and towards the end of 1601 

 he was suddenly seized with an illness which terminated 

 fatally after a few days (November 24th). It is charac- 

 teristic of his devotion to the great work of his life that 

 in the delirium which preceded his death he cried out 

 again and again his hope that his life might not prove to 

 have been fruitless (IVefrustra vixisse videar). 



109. Partly owing to difficulties between Kepler and 

 one of Tycho's family, partly owing to growing political 

 disturbances, scarcely any use was made of Tycho's instru- 

 ments after his death, and most of them perished during 

 the Civil Wars in Bohemia. Kepler obtained possession 

 of his observations ; but they have never been published 

 except in an imperfect form. 



no. Anything like a satisfactory account of Tycho's 

 services to astronomy would necessarily deal largely with 

 technical details of methods of observing, which would 

 be out of place here. It may, however, be worth while 

 to attempt to give some general account of his charac- 

 teristics as an observer before referring to special dis- 

 coveries. 



Tycho realised more fully than any of his predecessors 

 the importance of obtaining observations which should not 

 only be as accurate as possible, but should be taken so 

 often as to preserve an almost continuous record of the 

 positions and motions of the celestial bodies dealt with ; 

 whereas the prevailing custom (as illustrated for example 

 by Coppernicus) was only to take observations now and 

 then, either when an astronomical event of special interest 

 such as an eclipse or a conjunction was occurring, or to 

 supply some particular datum required for a point of theory. 

 While Coppernicus, as has been already noticed (chapter iv., 

 73), only used altogether a few dozen observations in 

 his book, Tycho to take one instance observed the sun 

 daily for many years, and must therefore have taken some 

 thousands of observations of this one body, in addition to the 

 many thousands which he took of other celestial bodies. 

 It is true that the Arabs had some idea of observing con- 

 tinuously (cf. chapter HI., 57), but they had too little 



