Observations on the Same Transit; and on an Eclipse of the Moon, May 8, 1761; and of the Sun, on the 3d of June 1761: In a Letter to the Rev. Thomas Birch, D. D. Secretary to the Royal Society, from Mr. Peter Wargentin, Secretary to the Royal Academy of Sciences in Sweden, and F. R. S.

"the clock, whenever he should call to him; "in which respect, he is of opinion, he made "no mistake, though, possibly, he might make "one with regard to the minute, by setting down "one too many at the egress; which he now "thinks there is some cause to believe he did." J. B. XXXVIII. Observations on the same Transit; and on an Eclipse of the Moon, May 8, 1761; and of the Sun, on the 3d of June 1761: In a Letter to the Rev. Thomas Birch, D.D. Secretary to the Royal So- ciety, from Mr. Peter Wargentin, Secretary to the Royal Academy of Sciences in Sweden, and F. R. S. Read Nov. 12, 1761. Litteræ hisce inclusæ, ad te et clarissimum Dollondium scriptæ, quas amicus meus, Dominus Klingensierna (principis Suec. hæreditarii præceptor) transmittendas mihi tradidit, occasionem mihi suppeditant, paucis te invi- sendi, tibique communicandi observationes nonnullas astronomicas, nuper à me habitas, in observatorio Stockholmiensi, cujus elevatio poli est $59^\circ 20' 31''$, differentia autem meridian. ab observatorio Grenovicensi $1^\text{h} 12' 1''$. Si illas dignas judicaveris, quæ illustrissimæ Socie- tati Regiæ offerantur, erit id mihi gratissimum. Quid- quid quid sit, me tua in scientias merita magni facere pro- fiteor, et sincero cum affectu sum, Reverendi nominis tui Cultor studiosissimus, Stockholmiae, die 9 Junii 1761. Petr. Wargentin, Acad. R. Scient. Suec. Secret. Eclipseos Lunæ totalis, die 18 Maii hujus anni, obser- vatæ, quædam momenta. Penumbra densa in margine Lunæ percipitur Initium veræ eclipseos circiter æsti- matum Grimaldus totus immergit Schickardus totus absconditur Galilæus occultatus in umbra disparet Gassendus delitescit Ariftarchus umbram ingreditur Tycho incipit immergere totus abit Copernicus incipit tenebris offundi totus fere absconditus Eratosthenes immergit Umbra ad Platonem Archimedes evanescit Plato totus est in umbra Plinius se subducit Proclus hæret in margine umbræ Vix apparet vestigium Procli Mare Crisium incipit immergere Idem totum tenebrae occuparunt Immersio Lunæ totalis in umbram 9 31 30 vesp. 9 32 20 9 35 50 9 38 48 9 39 47 9 43 28 9 48 10 9 51 5 9 52 18 9 54 16 9 55 48 10 4 0 10 14 53 10 15 26 10 16 50 10 18 31 10 29 38 10 30 28 10 31 30 10 35 24 Vol. I II. Margo tamen Lunæ, qui ultimus immerserat, satis clarâ luce conspicuus fuit per 5 vel 6 temporis minuta, et referebat nudis oculis speciem stellæ secundi ordinis. Hora autem 10h 52' ille ipse margo, cum tota reliqua Luna, ita prorsus disparuerat, ut nullum ejus vestigium, vel nudis vel armatis oculis, sensibile restaret, cælo licet sereno, et stellis vicinis in tubo conspicuis. Sub ipsa quoque immersione, illa Lunæ portio, quæ in umbram inciderat, penitus evanescerat, aliter fane quam fieri solet etiam in eclipsibus Lunæ centralibus; plerumque enim Luna, quamvis in medio umbræ, apparere solet lumine quodam subobscuræ, per atmosphæram refracto. Antequam autem Luna sic disparesceret, animadverti stellam (Librae) in vicinia marginis orientalis, quam Luna mox occultatura videbatur. Eam omni studio prosecutus vidi demum, oculi ictu citius, extinguui occultatam Ejusdem stellæ emersio contigit inter 11h 43' 8'' et 11h 43' 28'' Emergebat à parte Lunæ prorsus invisibili: ejusque sub Luna semita borealior paulo erat diametro Lunæ horizontali. Postquam Lunam amissam diu quaesivisset, reperi tandem tubo bipedali, hora 11h 30', vix sensibili luce circa marginem orientalem suffusam. Hora 11h 33' ejus quoque vestigium acutioribus se offerebat oculis, instar tenuissimæ nubeculæ. Plusquam dimidius autem Lunæ discus occidentalis manit prorsus invisibilis, et erant limites inter visibilem et invisibilem partem valde tortuosæ; circa margines autem Lunæ erat lumen illud intensius et magis extensum, quam circa centrum. Cœpta vero emersione, quidquid nondum emerserat, plane visum non feriebat. Lunæ margo juxta Grimaldum lucidior exsplendescere coepit Initium emersionis veræ circiter Grimaldus incipit emergere totus luei restitutus Galilæus prominet Aristarchus apparet jam totus est illustris Copernici nucleus lucem adspicit Tychonis nucleus incipit eluctari tenebris totus evasit Plinius prorepit Promontorium acutum incipit prominere Mare Nectaris totum emerit Snellius emergit Totum Mare Crisium luci restitutum Langrenus porrigit latus Finis vera eclipseos circiter Non nisi penumbra in Luna est residua Observationes hæ habitæ sunt cum tubo 9 pedum. Dominus Strömer, astron. prof. Upsaliensis, sociam mihi in observanda hac eclipsi commodavit operam, usus tubo 5 pedum. Ille pleraque immersionis momenta $20''$ vel $30''$ citius, emersionis autem tantundem fere tardius notavit. Eclipsis Solis, die 5 Junii. Sol ortus est hac die quartâ fere diametri horizontali parte mulctatus, hora Finis tantum hujus eclipseos utcunque observari potuit; contigit ille Transitus Transitus Veneris per discum Solis, die 6 Junii. Venus jam aliqua sui parte discum \{h\} \{3\} \{21\} \{37\} A.M. Solis occupaverat \{3\} \{39\} \{23\} Propter vehementem marginum Solis undulationem, primum contactum exteriorem accuratius notare non potui. Contactus interior, vel immersio \{3\} \{39\} \{29\} totalis, meo quidem judicio contigit At Dn Klingensierna contendit, eum demum contigisse \{3\} \{39\} \{29\} Initium emersionis, contactu interiore, certè mihi apparuit \{9\} \{30\} \{8\} Idem contactus ex observatione Domini Klingensierna \{9\} \{30\} \{11\} Finis emersionis vel contactus ultimus, ex judicio Di Klingensierna \{9\} \{48\} \{6\}, vel \{8\}. Meo autem, neutiquam ante \{9\} \{48\} \{9\} Ego hac occasione adhibui tubum 20 ped. Suec. cum oculari, focum ad 3 digit. distant. habente. Dominus autem Klingensierna usus est novo illo excellentissimo tubo Dollondiano 10 pedum, cum oculari medio, vel mediocriter objecta ampliante. Reliquas meas observationes circa hunc transitum nondum in justum ordinem redegi. Diameter Veneris in Sole erat quamproxime 5". Notatu dignum est, quod margo Veneris, qui jam emergerat, conspicendum se praebuerit etiam extra Solem, Solem, debili quadam luce, idque sub tota fere emer- sione, in hunc fere modum. Sive illa in margine Veneris apparens, inflectioni radiorum Solis, sive refracti- oni in atmosphæra Veneris, sit tribuenda, disquirant alii. XXXIX. An Account of the Observations made on the same Transit in Sweden: In a Letter from Mr. Peter Wargentin, Se- cretary to the Royal Academy of Sciences in Sweden, and F. R. S. to Mr. John Ellicot, F. R. S. Translated from the French. S I R, Stockholm, Aug. 7, 1761. Read Nov 12, 1761. In a letter, dated June 8th, I commu- nicated to Dr. Birch, Secretary to the Royal Society, my observations upon the transit of Venus. Having since received some other good ob- servations of this phænomenon, I thought the com- municating them to you, would give you some plea- sure. At Torneo in Lapland, Messieurs Lagerborn and Hellant very happily observed both the entrance and exit of Venus, with telescopes of 32 and 20 feet focal lengths. The principal times observed were as fol- lows: Exterior