( 2-l X

a;. Percipio Vestrates non omnes.mihi adstipulari in isto Dioptrarum Nego- *

tio, de quibus in Machinx mex Coelestis Organograpbia tractavi. Verum 'bj T *~

etiamsi Cl. Hookjus &C Cl.FUmßcdius, aliique, plane aliter sentiant, experientia M. Hevelius. .tamen quotidiana me edocuit, atque etiamnum docet, rem longe aliter se ha.- n ' 102 * f ' 27 ' ~berc in Magnis illis Organis, Quadrantibus scii. Sextantibus & Octantibus,imprimis Quadrantibus Azimuthalibus, aliisque Quadrantibus Regulis construrctis, qux. nempe adeo procliviter, commoveri Sc inverti, (dum examinanturDioptrx Telescopicx) imo nullo modo possunt, ut quidem Instrumenta illatrium quatuorve Pedum Perpendiculo constructa. Res cumprimis in eo con-sistit, quod nullam plane Observationem suscipere poliint luis Dioptris Tele-scopicis, nisi prius denuo eas Examinent, &c Rcctisicent; in quo tamen Extamine varia via idqqe jugiter,, utut studiosissime illud suscipias, hallucinari •datur. Ad hxc, in Quadrantibus Azimuthalibus, Octantibus & Sextantibus,qua ratione Examen illud omni tempore, commode,. & sine magno Tempo-ris Dispendio institui postit, profecto nondum capio.

Video etiam aliquos (inter quos Cl. Flamstedius invenitur) tulisse jam dsnostris Observationibus, qualibus qualibus, judicium, priusquam illas viderunt,

Examinarunt, vel quicquam de iis Cognoverunt. Nolo quidem vanus essererum mearum Jactator,, nec unquam imaginatus mihi fui, me in omni istoNegotio, Restitutionis scii. Fixarum rem acu omnino tetigisse, aut tangerepro mea tenuitate posse : Sed hoc mihi penitus imaginor, si quidem totum il-lud Negotium suscepissem Dioptris Telescopicis* milii non solum plurimos An-nos Examinibus terendos, sed. &. spe, sine dubio, varia via. (qua de rc hicnon est disserendi locus) cadendum suisse. Exinde gratulor mihi,, me ad sen-tentiam illam necdum transi iste,meacque me Methodo omnia perfecisse quicquidpraestitum Dei Beneficio fuerit. Quando vero Observationes.habebimus 10 Sczo Annorum spatio continuatas utrinque, nimirum tum qux Dioptris Teie?scopicis, tum qux solummodo nostris de Coelo depromptx suerim, res om-nino clarior sutura est. Interea suo quilibet Ingenio fruatur, remque scia rati.'one pro Libitu, tentet.

VII. i. It is v/ell knownthat the mean Apparent Magnitude os die Meos v% ceUstu:is 30 nun.. 30 lec. ve will take it Kumcro Retundo to be 30 min. at a EuIIbloon in the niidst os IV inter, and.when Ihe's in the Meridian, and .at hergreatest Northern Latftude, and consequently the utmost that ss.e can be-Ele? th* nvated in our Horizon j ’Tis as well knawn allo, that when fhe is in this Po?sture, bemgjooked upon by the Naked Eyc, fhe appears (that we may ac? AfrTwill. m<vcommodate ali to sensible Measures) to be Magnitudinis Pedalis, about a Foot llncu,c - lS 7-broad. But the farne Moon being lookcd upon just as fhe Ri(es r fhe appears 3 ' A ‘to be threc or four Foot broad, and yet if with an Instrument we take herDiameter, both in one Posture and the otlier, we-fhall sind that still fhe stialibe but 30 min. ThaCthis matter of Fact is true, besides- the Autnority ofmany Authors,. I can Assert that I have accuvately tricd it my seif, and 1 haveso found it : One os the wayS' I prpcceded was thus, I took a very ?ocd Tolescope of about 6 Foot long, ih the imvard-Focus of whofe Eye Olafs I an?pty’d a very sine Lattice made of the single Hairs of a ManV Hcad; Theo-..

Icoking ..