J46 ON TH£ TELESCOPE. 



Obfervations previoufly to remark that Sir H. Englefield has not afferled 

 relating to the t j iat Kepler was the original inventor of the telefcope. The 

 telefcope. on ty inference which can be juftly drawn from his words, is 



that they were invented as early as the year 1607. No one, 

 indeed, who had attentive!) read Kepler's dedication of his 

 Dioptrice, could have entertained fuch an opinion. He pre- 

 cifely ftates * that fince " ad magnum cumulum inventionum 

 hujus ultimi fbeculi accefliffet Aru'ndo Dioplrica, nequaquam 

 inter vulgares commemoranda machinationes, circaque earn, 

 alii de palma priuue inventionis cerlarent, alii de perfeclione 

 inftrumentt fefe jaftarent, .... Galilseus vero fuper ufu p?- 

 tefaclo in perquirendis arcanis Aftronomicis fpeciociflimum tri- 

 umphum agerel; .... Ego ductus honefia quadam asmulati- 



one novum mathematicis campum aperui caufarum 



lege geometrica demonftrandarum quibus . . . effeclus inni- 

 terentur." 



Before the invention of telefcopes, aftronomical obferva- 

 tions were fometimes made with tubes, but more generally 

 with rods (regular) which had fights fixed at each end. Thefe 

 inftruments were generally called Dioptra, and the apertures 

 in the fights were called foramina dioptrorum, not perfpicilla. 

 Ptolemy in his Alraegifi + defcribes the inftrument, which is 

 generally'knovvn by the name of hisTriquetrum. It had fights 

 at each end, with apertures in them, which Georgius Trape- 

 zuntius, the tranfiator, calls foramina : he mentions, indeed, 

 no particular name for this part of the inftrument, but Theon 

 in his commentary % defcribes the conftru&ion of it to be fuch, 

 that the whole moon would appear through the fights sj rn 

 dnffiw. Proclus Diadochus, in his Hypotypofis Aftromica- 

 rum Pofitionum,** mentions the Dioptra of Hipparchus, which 

 was an inftrument of the lame kind : fee Riccioli Almegiftum 

 Novum, vol. I. B. 3. C. 10. § 4. But we can have no fur- 

 ther doubt upon the fubjecl, if we turn to Flamftead's Hiftoria 

 Caeleitis, vol. III. p. 97. He there fays that " haud pauci 



*Pp. 53, 54. Lonci. 1653. f Book 5, chap. 12. 



% P. 258. Bafil, 153S. Notwithstanding what Harduinus fays, 

 I have no doubt, but that the Dioptra mentioned by Pliny in his 

 Natural Hiltory, B. 2 C. 69. was an inftrument of this kind; but 

 no defcription of it is given, and therefore I cannot argue upon it 

 in this place. 



**P. 399. Bafil, 1541. 



obfervationum 



