European clocks should have protnplrd them to 

 open their doors, previously so carefully and for 

 so long kept closed against the foreign barbarians. 



Mechanized Astronomical Models 



Now that we have seen the manner in which mech- 

 anized astronomical models developed in China, we 

 can detect a similar line running from Hellenistic 

 time, through India and Islam to the medieval Europe 

 that inherited their learning. There are many diffcr- 



Figure 4. — Astronomical Clock Tower of .Su 

 Sgun in K'ai-feng, ca. A. D. logo, from an original 

 drawing by John Christiansen. (Courtesy of Cam- 

 bridge University Press.) 



enccs, notably because of the especial development of 

 that peculiar characteristic of the West, mathematical 

 astronomy, conditioned by the almost accidental con- 

 flux of Babylonian arithmetical methods with those of 

 Greek geometry. However, the lines are surpris- 

 ingly similar, with the exception only of the crucial 

 in\ention of the escapement, a feature which seems to 

 be replaced by the influx of ideas connected with per- 

 petual motion wheels. 



88 



BULLETIN 218: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNONOGY 



