MEDI/EVAL SCIENCE AMONG ARABIANS 



the moon. Two inequalities of the motion of this 

 body were already known. A third, called the moon's 

 variation, was discovered by an Arabian astronomer 

 who lived at Cairo and observed at Bagdad in 975, 

 and who bore the formidable name of Mohammed 

 Aboul Wefaal-Bouzdjani. The inequality of motion in 

 question, in virtue of which the moon moves quickest 

 when she is at new or full, and slowest at the first and 

 third quarter, was rediscovered by Tycho Brahe six 

 centuries later; a fact which in itself evidences the 

 neglect of the Arabian astronomer's discovery by his 

 immediate successors. 



In the ninth and tenth centuries the Arabian city 

 of Cordova, in Spain, was another important centre 

 of scientific influence. There was a library of several 

 hundred thousand volumes here, and a college where 

 mathematics and astronomy were taught. Granada, 

 Toledo, and Salamanca were also important centres, to 

 which students flocked from western Europe. It was 

 the proximity of these Arabian centres that stimulated 

 the scientific interests of Alfonso X. of Castile, at whose 

 instance the celebrated Alfonsine tables were con- 

 structed. A familiar story records that Alfonso, 

 pondering the complications of the Ptolemaic cycles 

 and epicycles, was led to remark that, had he been 

 consulted at the time of creation, he could have sug- 

 gested a much better and simpler plan for the universe. 

 Some centuries were to elapse before Copernicus was 

 to show that it was not the plan of the universe, but 

 man's interpretation of it, that was at fault. 



Another royal personage who came under Arabian 

 influence was Frederick II. of Sicily the " Wonder of 



VOL. a. 2 



