Tycho Brahe is said to have abandoned belief in judicial 

 astrology in the later years of his life, while the younger 

 philosopher Kepler died in the position of professional astrol- 

 oger to the wealthy and powerful General Wallenstein, Duke 

 of Mecklenburg, at his residence in Silesia (1629). 



Rudolph was very well acquainted with the mechanic arts 

 and fond of collecting curiosities of mechanism, such as auto- 

 mata, peculiar clocks, and novel instruments for measuring 

 distances, models of machines for raising water, of windmills, 

 and of devices for facilitating the transportation of persons 

 and goods ; some of these were made by the celebrated me- 

 chanic Christopher Schissler of Augsburg, one of whose 

 quadrants is now preserved at Oxford. The Emperor had a 

 collection of models that would interest and amuse a modern 

 Patent Office examiner; among them were two odometers of 

 unusual construction that not only indicated the distance 

 travelled but recorded it on paper. One of these is said to 

 have been invented by the Emperor himself; they are described 

 by De Boot in his "Gemmarum et Lapidum Historia," and 

 one of them is figured by Athanasius Kircher in his "Magnes, 

 sive de Arte Magnetica," 1643. 



Rudolph was always on the lookout for novel inventions 

 that he thought could be turned to practical uses, and when 

 he learned that the problem of perpetual motion had been 

 solved by a Hollander named Cornelius Drebbel, of Alkmar, 

 he conceived that a machine endowed with self-producing 

 energy might be useful in the imperial quarries and mines. 

 Although Kepler and others tried to convince his Majesty 

 of the absurdity of perpetual motion, Rudolph invited Drebbel 

 to visit Prague. 



Drebbel was a skilled mechanic and an experimenter in 

 optics ; in a letter addressed to James I. of England, written 

 during his sojourn in London, he boasted of having determined 



93 



