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togcthcr ; and first, I aflert, That a wider or narrower Apertureos the Pupiiincrcales not, neither diminilhes the Projection on the Retina. I knovv, Hono-ratus Fabor in his Synopsis Optica endeavours to prove the ciear contrary to tinisnr/Aflertion, and that aster this manncr. AB is an Object, EF thegreaterAperture os the Pupii, admitting the Projection K I on the Retina, whereasthe lefler Aperture C D, admits only the Projection G H ; but GH is leisthau KI, wherefore a lefler Aperture diniiniflies the Projection. I admirethat any Man that undcrtook (as Honoratus Faber) to write os Optickj moreaccuratcly than all that went' before him, fliould be guilty of so very grossan Erruur ; and I do more admire, that the -Celebrated Gasicndus, and withliim the Noble Hevelius , fliould be of the fame Opinion: For tho’ theaforc-laid Demonstration hold most certainly true in direct Projections, as in auark Room with a pia in Hole ; yet it will not hold in Projections made byRefracticn, as it is in thole on the Retina in the Eyc, by means os the Cry-stalline and other Coats and Humours of the Eye. For let AB be a re-mote Object, and EF the Crystalline at its large Aperture, projecting theImage I M on the Retina. Let theil CD be the lefler Aperture of the Pupilbefore the Crystalline : Play, the Image I M fliall be projected as large asbefore, for the Cone of Rays E AF consists partly of the Cone of RaysCAD, therefore where the former E A F is projected, the latter C A D, asbeing a part of the former, fliall be projected also. So that no more is effe-cted by this narrow Aperture, but that the sides of the Radiating Cones areintcrcepted, and conlequently the Point I, fliall be aftected with lels Light,but it fliall still be in the lame place: what is sind of that Cone and thatPoint, niay bc (iiid of all other Cones and other Points of the Object. From

b.ence appears, First, Thc’Invalidity of the Account given of the Moon'sAppearance by Gajfcudus front this Reason. Secondly, The Reason appearsv.diy a Telefcopc's lefler or greater Aperture, makes no difference in the An-gle it reeeives: For imagine EF to be an Object Glals of a Tcldcope, and'tis plain. Thirdly, ’Tis Evident why a greater or leis Aperture on a Telc-icope fliould make the Objects appear lighter or darker, for thereby more orkls Rays are admittcd to determino on the Projection of each Point. But allthis by the by. And this is liiflicient for a Conkitation of Gajsitndus and Faber ;But our forementioned Abbe superadds to a greater or lefler Aperture of thePupil, as a neeeflary conlequent, a greater and lefler Convexi ty of the Cry-stalline, as also a lengthning and fliortriing the Tube of the Eye. And thisI nmst confis would do something, if we find it true in our Cafe ; and thislet us try. First, (iäys he) The duskiflinels of the Moon nigh the Horizon, admits the Pupil to en large it seif, the Crystalline to statten, and the Eye tokngthen .- but what if we change our Object, and instead of the Moon takethe Distance between lome of the Fixt Stars, ("as liippole thole of OrionsGiniic -) we.fliall find the lame Fhxnomcnon in them, and yet I hope neither,he nor Gaffcndus will aflerr, that tlicy at one time strain the Eye more than atanother, or that at any time their Fulgur strains the Eye at all; if he do, letbim take Stars of the lefler Magnitudes, nay even thole that can but just bepereeived, and then he will be convinccd: Or let him conlider whether this

will