^' 



S'S 



MATHEMATICAL and 





vations, of the firft fatellite, rejefting that of the i6th of 

 May, to reduce them to the meridian of Philadclphiaj and 

 if they are then compared with the calculations in the nau- 

 tical almanac; we ihaill have tlic fame rcfult from them 

 alfo. 



The calculated time per Nautical Al- 



Greenwich ojbfcrvatioas re- 



Dtiference of meridian of 





?nanac. 



duced 



to the niciidian oi 



Greciiwkh ynd Pbila.- 



1 





Phitad 



clpliia. 



dciphia. 





1769. D. h. m. fcr.. 



n. 





h. m, f^'c. 





Afar. 29, 1%. %4. 26 Tm. ift. 



29, 



7. 24. 3a 



4- 59- 54 





ylf'tU 12, 16. 16. 13 iiu. III. ■ 



12, 



II. 15. 3^ 



5. 0. 35 





28, 14, $6. 14 Im. if!:. 1 



.28, 



9. 34. 42 



5- I. 3^ 





Jt//?e 8, 9> 41. 26 Em. ift:. 



8, 



4- -lo. 41 



5- 0. 45 , 





35) 31- 34- 55 ^m. iflo 



I5» 



6, 34, 58 



4- 59- 57 





yi/Iy J, 9. 50. 37 Em. lO. 



I, 



4. 49- 49 



5. 0. 48 





!ff//nV II, 14. 50. 4 Im.2d. 



II, 



9. 49- 48 



5. 0. 16 



^ 



ilfa^- 6, II. 51. 45 Im. ad. 



t', 



6, 50. 27 



J. I. 18 





The mean of thefe determinations of thclon^itude>from 





the Green w^ich obfcrvations 



of the firft fa 



telHte, is 5\ 0'. 



\ 



^^^\ But farther if we take tlie mean of all the determina- 

 tions, derived from the eclipfes of the fecond fatellite, it 

 will be found to be ^^\ o\ 37''. And laftly, if the mean 

 of all the determinations from the eclipfes of both firft and 

 fecond fatellite be chofen, the deduced longitude will be 



«h 



o 



/ 



.-/' 



5 ' ^ • 35' * ^^^ ^^^^t ^^ ^^y f^fely conclude, that the dif- 

 ference of meridians between Philadelphia and Greenwich, 



is 5\ o'. 2^^'; and that Norriton is ^6^' of time weft of 

 Philadelphia, and its longitude is 5\ i^ 31'^ weft. With 



this determination we muft be contented until farther ob- 



-^ 



fervations are made, by which it may be confirmed, or ren- 



dered liable to exception. 



Thefe obfcrvations are fufficlent to determine every thing 

 relative to the theory of Venus, and the parallaxes of the 

 Sun and planets, as may be feen by the annexed projec- 

 tion of the tranfit, and the following calculations. Al- 

 though the parallax of the Sun may be obtained from the 

 obferved neareft diftance of the centers of the Sun and 

 Venus, yet this method cannot be fo much depended on, 

 as the comparifon of the contacts of the limbs obferved in 

 proper places, where the abfolute difference of time is 

 confiderable. Nevcrthelefsj as the public feem very impa- 

 tient 



