VOL. I.] PHILOSOPHICAL TRANSACTIONS. 53 



and published, both in Persian and Latin, by Mr. Thomas Hyde, now library 

 keeper to the Bodleyan Library in Oxford, with commentaries of his annexed ; 

 like as another part of it has formerly been by Mr. John Graves. And it would 

 be a commendable thing to translate the whole, that we might be the better 

 acquainted with what the eastern astronomy at that time really was. 



Appendix to the Directions for Seamen bound for long Voyages. 

 By Mr. Hook. N*" 9, p- 147- 



This paper is repeated, and much enlarged, in N° 24, where it is given in a 

 more perfect state. 



0)1 the Differeiice between two learned Men, about an Observation 

 made of the first of the tivo late Comets. N° 9, p- 150. 



As it has been noticed in Number 6, that there was some difference between 

 those two deservedly celebrated philosophers, M. Hevelius and M. Auzout, con- 

 cerning an observation made by the former on the ^ \ of February 1 665 ; and 

 that thereupon some eminent English astronomers, considering the importance 

 of the dispute, had undertaken to examine it ; it is conceived that it will not be 

 unacceptable to present the result to the reader of these papers. Having 

 therefore compared the printed writings of the two disputants, and consulted 

 the observations made with telescopes at home, by some of the most intelligent 

 astronomers amongst them, who have attentively observed the relative position 

 of that comet to the telescopic stars that lay in its way, they conclude that what- 

 ever that appearance was which was seen near the first star of Aries, by M. 

 Hevelius, (the truth of whose relation concerning the same they by no means 

 question) the said comet did not come near that star in the left ear of Aries, 

 where the said M. Hevelius supposes it to have passed, but took its course near 

 the bright star in its left horn, according to Bayer's tables. And the same is 

 also confirmed by the observations of other astronomers in France, Italy, and 

 Holland. 



Of finding the true Distance of the Sun and Moon from the Earth, by 

 the observed Parallax. iV° 9> p- 151. 



The discovery of this distance may prove of important use for the perfecting 

 of astronomy, and for better establishing the doctrine of refractions. 



To perform which the following method is proposed, viz. That, at certain 

 times agreed on by two observers, using large and proper telescopes, with a 

 measuring rod, placed within the eye-glass at a convenient distance, that it may 



