% 



J 



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swjd ecKptical conjundion. 



MATHEMATICAL and 



I. 8:^4,948o5^66",8264^T the length of part of the tranfit line between 

 %. 551,0104 5 hor. motion whe middle of the tranfit and the ecjipt. con- 

 — . in feconds. j junction. 



— I. a73,9376=^oh. i87205~oh. xi' . i6^',458=the time between the middle 



9,74,338=^the fum of the fcmidlanrctcrs of and $J .. 

 455,024:^thegeo. ncarejl: dift. ofthcir centers.. 



< ^ 



Sum--i429,362-=3. 155.142^ 

 Diff.= 5IMI4=^^- 715.4300 



a)5. 870,572^ 



or Of. II -/■* ? ^^If *^^c Icne-th of the tranfit line from the 

 2., 93J,j86l=86l",56r \ external contadl.^ 



%. 55 1, oro4^=thc horary motion of ^ on 0, as feen from Q. 



o. 384,2757=2h. 4a^567=3::'2h.'4aa567=ah. 25'. ai'^a4.the fcmidur;*'- 



tion from the external contad;. 



965,862, the diff. of thefemidiametcrs of and tji . 



455,024 the geo. nearcfl diftance of their centers.. 



Sum~i42o,886=:3. 15^,5691 

 Difr,=-5io,738z:=:2. 708,2833 



2 ) 5. 860,8524 



a. 930,4262= 

 2. 551,0104= 



55l,9743=thc length of half 



internal contai5l, 

 or. mot. of 5 - 



the tranfit line from the- 



o. 379.4i58=2h. 3956i==2h. 23'. 44",I96 



Kow to ih. ^&. 19" the time of the external conta6t, 



Add %. 25. 21 the fcmldur. between the external contac5ls. 



The Sum, 

 To this add, 



The fum, 

 To this add, 

 The fum, 



5. I. 30 is the time of the neareft approach of their centers. 



II. 16,5 the time from the middle to the eel. conjunt^tion. 



5. 12. 46,5 isthcapparcnt timeof theech conjun<5lion at Philadelphia. 



5, o. ZS the diff. of meridian?; between Greenwich and Philadelphia. 



10. 13. 21,6 is the time of the ccl. conjuniilion at Greenwich, when the 

 $un*s place, according to the Nautical Almanac, 13 7s. 17^^- 50^. 41'', and that of Mercury Js 

 15.17*^-50'. 41", by I)r.Hallcy's tables. From this fubtratSt 2". 15'. 12", the Sun's diilance 

 from the node of Mercury, and the remainder is. 15°. 2,S'- 39", is the place of his node at that 



time. 



The Projection oftheTKK^^ir ^MERCURY, PL V. 



THE following projedlon of the tranfit of Mercury 

 over the Sun, on the 9th of November, 1769, was made 

 from the foregoing meafures and calculations, 011 thefup- 

 pofition that the Sun's horizontal parallax, at his mean dif- 

 tance is 8'', 65, and therefore, 8^^,7437 on the day of the 

 tranfit. In this cafe, the horizontal parallax of Mercury, 

 at his mean diftance, will be 14^^1132, and on the day 

 of the tranfit 1 2^^7856, and therefore his horizontal pa- 

 rallax from the Sun on that day is 4'',04i9, being the dif- 

 ference of their parallaxes. 



The delineation was made In the fame manner as that of 

 the tranfit of Venus. The elements for it were colleded 



\ from 



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