MECHANICS. 345 



of their proper places. Many other minor pieces on astronomy and 

 optics are also attributed to this author ; but we have already extended 

 our accounts of his works to a greater length than we had intended, 

 and must now therefore pass on to his successors. 



After the time of Ptolemy we find no Greek astronomers of Greeks 

 eminence, although we have some few writers on this subject. The 

 science of astronomy had now obviously passed its zenith, and began 

 rapidly to decline. The Alexandrian school, it is true, still subsisted ; 

 but during the long period of five hundred years, all that can be said 

 is, that the taste for, and the tradition of, the science was preserved, by 

 various commentators on Hipparchus and Ptolemy ; of whom the most 

 distinguished were Theon and the unfortunate Hypatia, his daughter. 

 The latter is said to have herself computed certain astronomical tables, 

 which are lost. 



We now arrive at that period, so fatal to the Grecian sciences. Destruction 

 These had for a long time taken refuge in the school of Alexandria ; Alexandrian 

 where, destitute of support and encouragement, they could not fail to school, 

 degenerate. Still, however, they preserved, as we have said above, 

 at least by tradition or imitation, some resemblance of the original ; 

 but about the middle of the seventh century, a tremendous storm arose 

 which threatened their total destruction. Filled with all the enthu- 

 siasm a military government is calculated to inspire, the successor of 

 Mahomet ravaged that vast extent of country, which stretches from the 

 east to the southern confines of Europe. All the cultivators of the 

 arts and sciences who had from every nation assembled at Alexandria, 

 were driven away with ignominy : some fell beneath the swords of their 

 conquerors, while others fled into remote countries, to drag out the re- 

 mainder of their lives in obscurity and distress. The places and the 

 instruments which had been so useful in making an immense number 

 of astronomical observations, were involved with the records of them, 

 in one common rain. The entire library, containing the works of so 

 many eminent authors, which was the general depository of all human 

 knowledge, was devoted to the devouring flames, by the Arabs ; the 

 caliph Omar observing, " that if they agreed with the Koran, they 

 were useless ; and if they did not, they ought to be destroyed' :" a senti- 

 ment worthy of such a leader, and oif the cause in which he was en- 

 gaged. In the midst of this conflagration, the sun of Grecian science, 

 which had long been declining from its meridian, finally set; never, 

 perhaps, again to rise in those regions once so celebrated for the culti- 

 vation of every art and science that does honour to the human mind. 



II. MECHANICS. 



It is not our intention, in the present article, to enter upon the history 

 of practical mechanics, but to confine ourselves exclusively to the 

 theory of the science ; we shall not, therefore, have to travel into those 

 dark ages in which historical facts and fables are so blended, that it 



