Instruments of file Ani'ients. 15 



lowing for the mistakes of historians ignorant of optics, 

 has made extremely probable, not to say absoiutely certain, 

 *o those at least, who have the opportunity of rcpcatino; his 

 very interesting experiments. Abidfeda, says M. de Biif- 

 fon, in his Description of Egypt, has these words : — " /« 

 Pharo Alexandrice, erat speculum, e ferro S'mico, per qnod 

 a longt videhantur naves Grcecorum advenieiites ; sed paulo 

 postquam islamismus invabdt, scilicet tempore ccdi/'atus 

 Walid-fit Abdilmelech, Christiani, fraude adhibita, illud 

 deleverunt', that is, In the Pharos of Alexandria was a mir- 

 ror of Chinese iron, by means of which the Grecian fleet, 

 when at a great distance, was seen approaching ; but, soon 

 after Mahometanism prevailed, the Christians destroyed it, 

 by stratagem * ." In Bujf'on's opinion, the words je'no Si- 

 nico ought to be rendered acier poli, or polished steel. But 

 this interpretation applies only io ferro, the abl. sing, of 

 Jerrum iron, and improperly excludes Siriico. I say impro- 

 perly ; for, of whatever kind the metal \\'as, the historian 

 certainly meant that it was Chinese. But why Ptolemfs 

 opticians should have sent to China for iron or steel, which, 

 the Sacred Writers assure uj, were conmion in Egypt, does 

 not appear. Being thus uncertain as to the precise kind of 

 metal of which this famous telescopic mirror was composed, 

 may we not ask, Whether Abulfeda, a historian who, it 

 seems, was not over accurate, might not have written 

 ferro for what is known lo us by the name of Tutanag, a 

 Chmese metallic compound, which might be valued then, 

 as it is now, for the high polish it receives f 



11. The Rev. Mr. Nixon's '' Dissertation on the Anti- 

 quity of Glass Windows," in the Philosophical Transac- 

 tions for 1758, mentioned above, is a sequel of " An Ac- 

 count of some Antiquities discovered at Herculaneum," in 

 the volume for 1 737. In the 1 3th article of this last paper, 

 one of those subterraneous antiquities is described as " A 

 flat piece of white glass, taken off from towards the extre- 

 mity of the sheet; as appears from the curvature and pro- 

 tuberant thickness of one of ;ls sides above the other parts." 

 Abat, perhaps, views Nixon too much in the light of an 

 opponent; for I do not find that the latter advances any- 

 thing inconsistent with the argume:\ts and proofs of the 

 former, except this observation .- — <■' Before the application 



•In Playjair's Chronoloj^y wc find xhT^Kiralicil.. calif of rhc Saracens, 

 reigned from A. D. 705 to 715. and lF«/u/ 11. from A.D. 743 to 744.-, 

 also that Ishnael MulJeUu, prince of Hamah, " an indiflereni geogra- 

 pher and historian," was born A. D. 1273, and died in 1343, 



of 



