"f^r r 



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ASTRONOMICAL PAPERS 



X75 



But the AftronomerRoyal write 



3 me 



5 that he has under 

 taken the final fettlement of this matter 



audi no doubt, 



he has feveral obfervations (whereon to found comparifons^ 

 that have not come to our baud, and will likewiJ'e confider 

 every nicety that can enter into this truly delicate calcula- 

 tion, making the proper allowances for the dilFerence of 





telefcopes, &c. I therefore thought it nccdlcfs to be very 

 particular in my comparifons, and contented myfelf with 

 thofe places whofe latitude and longitude could be well 

 depended on, and where tlic iky was clear, and the Sua 

 any tolerabie height above the horizon. Indeed, fome of the 

 ten places in the above table ought, perhaps, to be rejected. 

 The longitude of Glafgow, for inilance, does not fecm 

 fully determined. For the ccllpfcs of Jupiter's fatellitcs, 

 obferved there by Dr. Wilfoth would give the longitu 





different from what the Dodor calls it in bis account of" 

 the tranfit, If that obfcrvation w^ere left out, the mean 

 parallax would come out a fmall fraftion larger by the ex- 

 ternal coatad. 



As to the parallax deduced from the internal contad, 

 viz. 7''5447on the day of the tranfit, I think no dependence 

 can be placed upon it, for the reafons given above. For 





unlefs our internal contads had all been noted about 22 

 later, they would not give the fame quantity of parallax 

 as the external contaas. And the truth of obfervation 

 would by no means permit us to lengthen out our internal 

 contacts fo much; for, in 22^' after the times noted by us, 

 Venus appeared not only furrounded wholly by the Sun's 

 light, but a confiderable way within his diflc, And indeed 

 the aftronomers in Europe, fecm fenfible of the little de- 

 pendence that can be placed on obfervations madefo near 

 the horizon, as thofe of the int. cont, 

 V Monfieur Ferncr whites from Stockholm, that he is more 

 furprized that ** the times or the contads fliould agree fo 

 well together than he is at their difference. For the near- 

 nefs of the Sun to the horizon, and the extraordinary quan- 

 tity of vapors with which the atmpfphere was loadec!, not 



only 



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