210 G E R A R D I R E G N E R I F C K E N S 



Sed pi^rlegenda est ipsa celebris asironomi scriptiuncnla ('): 



« The Royal Society have comc to a resolulion to send pcrsons of abilily to proper 

 « places, in order to observe the approaciiiiig passage ol Venus over Ihe sun , llie 6'^ of 

 « June nextyear; (which phaenomeuon was fiist proposed to this Society, by Ihe late 

 « excellent Dr. Halley, forly-four years ago , as a proper mean of delermining the 

 « sun's pdrallax , to a great degree of exactness). I taice this opportunity of recommen- 

 <( diu" to llie consideratiun of this learned body an.jlher very important object in astro- 

 h nomy, which, I apprebend, may be cleared up at Ihe same time , by the astrono- 

 « mers scnt to one of ibose places, which will probably be judged convenient für the 

 « Observation of Vcnus's transit; I mean the island of St. Helena. 



« The aslronomical object , in favour of which I desire to engage your attention , is 

 « no less than the delerminalion of the annual parallax of Ih« orbis mngnus; the finding 

 « out of wbich , from Observation , would be tlie füllest and direclest proof of the Co- 

 « pernican syslem , as the want of this proof, bitherto, has been Ihe strengest argument 

 <( made use of by those , who have with-held their assent to an hypjlhesis, which so 

 u fiilly, and yet simply, satieües all the olher phaemmena, 



(1 No one, indeed , at this time of day, will venture to asserl, that , even if no an- 

 te nual parallax could be found, after the grealest exertion of human art and industry, 

 « the C'ipernican System was not, therefore, true; since llie cjuantily of this parallax 

 K may be so small , as to escape the reach of our sighl , thougb assisted to the utmost. 

 « But thougb Ihe dcfect of it would be no just argument against Ihe Copernican System, 

 « yet the aclual demonstration of it, from Observation, would be a direct and con- 

 6 vincing proof of the truth of that syslem, 



« It remains then to be considered , wbat bope Ihere is now left , afler astronomy 

 « has been brought to such a great degree of perfeclion , of beiiig able to find out aa 

 « annual parallax in any of the fixed slars. 



« I am sensible I may here seem to be presumptuous , in venturing to treat upon this 

 « subiect , after the many accurate observations made by the learned Dr. Bradley, 

 « with an instrument .constiucted for this very pnrpose. No one can have a Ingher ve- 

 « neralion than I have for the discernmcut and exactness of this illuslrious astronomer, 

 « wliose merit I have the greater opportunity of being acquainted with , by having the 

 « boaour of calling liim my frieud. I would just beg leaye to take nolite , that the 



« Stars, 



( • ) Phil. Trans. 1 7B0. Vol LT. P. 11. n". 78. p. 889. Titulus est t A Proposal for discofering 

 ihe Annual Parallax of Sirius ; by the Bev. INevil Maskelyne, A.M. FeUow ofTrinitjr College, 

 •Cambridge and JF, R, S." Cai-ul: Read Juae iQ , 1360. 



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