Figure i6. — Islamic Pump Powered by a Weight Dri\t., after the text cited in fii;iire 14, 



The devices include a many chambered wheel (see fig. 

 14) similar to the Alfonsine mercury "escapement," a 

 wheel of slanting tubes constructed like the noria (see 

 fig. 15), wheels of weights swinging on arms as 

 described by Villard of Honnecourt, and a remark- 

 able device which seems to be the earliest known 

 example of a weight drive. This latter machine is a 

 pump, in which a chain of buckets is used to raise 

 water by passing over a pulley whicii is geared to a 

 drum powered by a falling weight (see fig. 16); 

 perhaps for balance, the whole arrangement is made 

 in duplicate w-ith common a.xles for the corresponding 

 parts. 



The Islamic tradition of water clocks did not invoke 

 the use of gears, though very occasionally a pair is 

 used to turn power through an angle when this is 

 dictated by the use of a water wheel in the automata. 

 In the main, everything is worked by floats and 

 strings or by hydraulic or pneumatic forces, as in 

 Heros devices. The automata are very elaborate, 

 with figures of men, monkeys, peacocks, etc., sym- 

 bolizing the passage of hours. 



MEDIEVAL EUROPE 



Echoes from nearly all the developments already 

 noted from other parts of the world are found to 

 occur in medieval Europe, often coming through 



channels of communication more precisely de- 

 terminable than those hitherto mentioned. Before 

 the influx of Islamic learning at the time of tran.s- 

 mission of the Toledo Tables (12th century) and the 

 Alfonsine Tables (which reached Paris ca. 1292), 

 there are occasional references to the most primitive 

 mechanized "visual aids" in astronomy. 



The most famous of these occurs in an historical 

 account by Richer of Rheims about his teacher 

 Gerbert (born 946, later Pope Sylvester II, 990-1003). 

 .Several instruments made by Gerbert are described 

 in detail; he includes a fine celestial globe made of 

 wood covered with horsehide and having the stars 

 and lines painted in color, and an armillary sphere 

 having sighting tubes similar to those always found 

 on Chinese instruments but never on the Ptolemaic 

 variety. Lastly, he cites "the construction of a 

 sphere, most suitable for recognizing the planets," but 

 unfortunately it is not clear from the description 

 whether or not the model planets were actually to 

 be animated mechanically. The text runs: -" 



Within this oblique circle (the zodiac on the ecliptic 

 of the globe) he hung the circles of the wandering stars (the 

 planets) with marvellous ingenuity, whose orbits, heights 



-' Once more I am indebted to Professor Loren MacKinncy 

 and Miss Harriet Lattin (sec footnote 11) for making their 

 collections on Gerbert available to me. 



102 



BULLETIN 218: CONTRIBUTIONS FROM THE MUSEUM ()!■ HISTORY .AND TECHNOLOGY 



