BIANCHINI, or BLANCIIINUS, FRANCIS, a ma. thematician and astronomer, who is chiefly remark. able for the dispute between him and Cassini, respect. ing the diurnal rotation of Venus, of which we have already given a full account in the article ASTRONO MY, p. 622. Bianchini was born of a family of rank at Verona, on the 13th of December 1662, and was educated for the clerical profession. After obtaining the degree of doctor in divinity, he was appointed li brarian to Cardinal Ottoboni, afterwar4; Pope Alex ander VIII., and was subsequently prbinoted to two canonries in Damaso. His mathematical knowledge obtained him the situation of secretary to the congre gation for the reform of the calendar ; and, on this oc casion, he published two dissertations, entitled, De Calendario ct Cyclo Ccesaris, ac de canone Paschali Sancti Hippolyti Martyris. In his work, De NUMMO et Gnat:one Akmentitio, he gives an account of his operations in tracing the meridian line in the church of the Chartreux, at Rome ; in memory of which, Clement XI. ordered a medal to be struck. During eight years he was employed in continuing the meri dian through the whole of Italy, and when engaged in this occupation, he was cut off by the dropsy, on the 2d of March 1729. Though Bianchini has not left behind him any lasting monument of his talents, yet such was the reputation of his learning, that he was admitted a foreign associate in the Academy of Sciences at Paris, in I706 ; created one of the nobi lity of Rome ; and the inhabitants of his native city erected a bust to his memory in the cathedral of Ve rona. Besides the works already mentioned, he pub lished, in 1726, a treatise on the discovery of a sub terraneous building, entitled, Camera ed Inscrizioni Sepolcrati di Liberti Servi, ed 9fficirdi della casa di Augusto, 4-c. ; in 1728, his Ilesperi et Phosphori Nova Phenomena, 8 c. ; in 1680, his Dialogo Fisico .Astronomico contro it sistema Copernicano, 4to. ; in 1684, his Cometes anno 1684 mensibus Junio et Ju lio, Rance Observatus ; in 1684, his Nova Methodus Cassiniana Observandi parallaxes et distantias Pla netaria: a terra; in 1703, his Solutio Problematis Pa s chalis, &c. ; and, in 1697, appeared the first volume of a great work on universal history, entitled, La Istoria Univcrsale provata con monumenti, et figurata con Simboli de gli Antichi, Syc. ; and an edition of Anasta= sius's Lives of the Popes, with dissertations and notes: A posthumous work, with plates, entitled, Francisci Bianchini Veronensis utriusque Signaturce referen darii, et prclati dontestici, de tribus generibus instrzi mentorum musicce veterum organicce dissertatio, was published at Rome in 1742, in 4to. The various papers which he wrote will be found in the Memoirs of the Academy for the years 1702, 1703, 1701.,
1706, 1707, 1708, 1713, and 1718. In 1737, Eusta chio Manfredi published the observations of Bianchini, under the title of Francisci Blanchini observationes selectee Astronomicce et Gcoffraphicer, ROMCC et alibi per Italian: habiter, ex vus autographis excerpter, una cum geographia meridiani Tabrilii, a mart m ixt.° ad tqferum, ex iisdern observationibus colkcta i et concinnata ; Veronz,fol. Among the observa tions of Bianchini, those upon Venus arc very singular; and we are much at a loss whether to consider them , a? absolute fabrications, or as the result of optical illusions which he had not the sagacity to discover. The disadvantages attending the use of the ls,*.ig re fracting telescopes were considerably, though not al together, removed by the contrivance of Huygens, by which tubes were rendered unnecessary. In 1712, Bianchini brought to Paris a contrivance of his own for the same purpose, which was described in the memoirs of the academy for 1713. With long te lescopes, to this invention was adapted, he seems to have ,observed Venus with unremitting assi duity. He perceived, or thought he perceived, seven large spots towards the middle of her disc, which communicated with one another by four straits ; and towards the extremities of her disc he observed other two spots, which had no communication with the former. He saw even promontories or projections of these dark regions into the lighter part of her disc. In imitation of Riccioli, he called those spots and promontories after eminent men, among whom 'were, the king of Portugal, Galileo, Caasini, Colum bus, Vespucius, Magellan, and several Portuguese ge nerals who had distinguished themselves by their conquests in the Indies. From the change of posi tion in these spots, Bianchini concluded that Venus revolved about her axis in 24 days 8 hours. It is a very remarkable circumstance, that the admirable te lescopes employed by Herschel and Schroeter have never yet been able to discover any of these spots perceived by Biauchini ; and we are the more inclined to suspect some great source of error, as it is now proved, by the accurate observations of Cassini, Her schel, and Schroeter, that Venus revolves about her axis in a little less than 24 hours, instead of 21 days, as Bianchini determined. For farther information re specting the life of this author, see his Eloge in the Hist. Acad. Par. 1729 ; in the .1sionvelles Literaires de Leipzig, Jan. 1731 ; and in Fontenelle's Eloge dei Aeademiciens, in the C.Euvres de Fontenelle, tom. vi.
p. 213. See also La Lande's Voyage (Phalle, tom. iv.
p. 311, edit. 1786. (o)