$ 6365] Ulugh Begh : Esti/nate of Arab Astronomy 83 



of our present system of writing numbers, by which the 

 value of a numeral is altered by its position, and fresh 

 symbols are not wanted, as in the clumsy Greek and 

 Roman systems, for higher numbers. An immense sim- 

 plification was thereby introduced into arithmetical work.* 

 More important than the actual original contributions of 

 the Arabs to astronomy was the service that they perform jJ 

 in keeping alive interest in the science and preserving the 

 discoveries of their Greek predecessors. 



Some curious relics of the time when the Arabs were 

 the great masters in astronomy have .been preserved in 

 astronomical language. Thus we have derived from them, 

 usually in very corrupt forms, the current names of many 

 individual stars, e.g. Aldebaran, Altair, Betelgeux, Rigel, 

 Vega (the constellations being mostly known by Latin 

 translations of the Greek names), and some cdfnmon 

 astronomical terms such as zenith and nadir (the invisible 

 point on the celestial sphere opposite the zenith) ; while 

 at least one such word, almanack, has passed into common 

 language. 



65. In Europe the period of confusion following the break- 

 up of the Roman empire and preceding the definite formation 

 of feudal Europe is almost a blank as regards astronomy, 

 or indeed any other natural science. The best intellects 

 that were not absorbed in practical life were occupied 

 with theology. A few men, such as the Venerable Bede 

 (672-735), living for the most part in secluded monasteries, 

 were noted for their learning, which included in general 

 some portions of mathematics and astronomy ; none were 

 noted for their additions to scientific knowledge. Some 

 advance was made by Charlemagne (742-814), who, in 

 addition to introducing something like order into his 

 extensive dominions, made energetic attempts to develop 

 education and learning. In 782 he summoned to his court 

 our learned countryman Alcuin (735-804) to give instruction 

 in astronomy, arithmetic, and rhetoric, as well as in other 

 subjects, and invited other scholars to join him, forming 

 thus a kind of Academy of which Alcuin was the head. 



* Any one who has not realised this may do so by performing 

 with Roman numerals the simple operation of multiplying by itself 

 a number such as MDCCCXCVIII, 



