As mentioned in the preceding chapter...
As mentioned in the preceding chapter, the latter leads to an error of one day in 3,330 years whereas al-Khayyam's leads to an error of one day in about 5,000 years. 'Umar al-Khayyam performed experiments to find the specific gravity of various substances. The attraction of iron by natural magnet was known to the Greeks; magnet's acquiring a definite direction when suspended freely was known to the Chinese.
But it appears that this property was first utilized by Muslims in their marine navigation. Muhammad al-'Aufi was the first to mention it in his Jawami'. The directive position of the…
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