Page:Catholic Encyclopedia, volume 2.djvu/764

 BOSCOVICH

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BOSCOVICH

survey in B-iZil. He volunturily offered his services for the arduous task, hoping thus to be able to carry out an independent sur\'ey in Ecuador, and so obtain data of value for the final solution of the problem of the figiu-o of the earth, which was then exciting much attention in England and France. His proposal led to the institution of similar surveys in the Papal States, the pope taking tliis means of retaining him in his own domain. A detailed account of the results of the work appeared in a large quarto volume (Rome, 1755) entitled: " De litteraria expeditione per Pontificiam ditionem ad dinietiendos duos meridiani gradus et corrigen lam mappam geographicam ". A map of the Papal States made at the same time, which corrected many previous errors, proved to be likewise a welcome contribution to the discussion re- garding the more or less spherical form of the earth. Many of the triaugulations were accompanied by no slight difficulties. The two base-lines employed in the survey — one on the ^'ia Appia, the other in the neighbourhood of Rimini — were measured with great care. The first was redetermined in 1854-55 by Father Secclii, as the mark indicating one end of the line measui'etl by Boscovich and Le Maire hatl been lost. (Cf. Secclii 's work: Misura ilella Base trigonometrica esequita suUa via Appia per ortline del governo pontificio, Roma, 1S5S.) Besides his work in mathe- matical astrono:uy we also find Boscovich speculat- ing, upon scirniilic L;rounds, on the essence of matter and endea\durii< in isiablish more widely Newton's law of miiwrsLiI iiravitation. As early as 174S we meet essays from his pen in this field of thought, e. g. "De materiiE divisibilitate et de principiis corporum dissertatio" (1748); "De continuitatis lege et ejus consectariis pertinentibus ad prima materia? elementa eormnque vires" (1754); "De lege virium in natura existentium" (1755); " Philosophiie naturalis theoria redacta ad unicam legem virium in natura existen- tium" (1758). Boscovich, according to the views expressed in these essays, held that bodies could not be composed of a continuous material substance, nor even of contigvious material particles, but of in- numerable, point-like structures whose individual components lack all extension and divisibility. A repulsion exists between them which is indeed in- finitesimal but cannot vanish without compenetration taking place. This repulsion is due to certain forces with which these elements are endowed. It tends to become infinite when they are in very close proximitj', whereas w-ithin certain limits it diminishes as the distance is increased and finally becomes an at- tractive force. This change is brought about by the diverse directions of the various forces. Boscovich divided his last-mentioned exhaustive work into tlu-ee parts, first explaining and establishing his theory, then pointing out its applications to me- chanical problems, and finally showing how it may be employed in physics. His attempt to reduce the most complicated laws of nature to a simple funda- mental law aroused so much interest that in 1763 a third, and enlarged, edition of his "Theoria philo- sophise naturalis" (Venice, 1763) had become neces- sary. The publisher added as an appendix a cata- logue of Boscovich 's previous works. There are no less than sixty-six treatises dating from 1736 — a

Croof of his literary activity. Some have already een mentioned and to these may be added his "Elementorum matheseos tomi tres", in quarto (1752).

Boscovich attracted attention by his political ■nTitings as 'well as by his scientific achievements. His Latin verses in which he eulogized the Polish king, Stanislaus, Pope Benedict XIV', and various Venetian noblemen, were read before the Arcadian Academy of Rome. His "Carmen de Soils ac Lunse defectibus" (o vols., London, 1760) was much ad- mired. His services were also in demand in several

cities and provinces. Thus, in 1757, he was sent by the city of Lucca to the Court of Vienna, to urge the damming of the lakes which were tlireatening the city. He acquitted himself of this task with such skill that the Luccans made him an honorary citizen and rendered him generous assistance on his scientific journeys, both in Italy, France, and England. AVhile in England he gave the impulse to the observations of the approaching transit of Venus, on 6 June, 1761, and it is not unlikely that his proposal to employ lenses composed of liquids, to avoid chromatic aberration, may have contributed to DoUond's suc- cess in constructing acliromatic telescopes. The citizens of Ragusa, his native town, besought him to settle a dispute in which they had become involved \\'ith the King of France — an affair which the pope liimself deignetl to adjust. Boscovich returned from England in company with the Venetian ambassador who took him by way of Poland as far as Constanti- nople. He availed himself of this opportunity to extend and complete his archaeological studies in these countries, as may be gathered from liis journal published at Bassano in 1784: "Giornale d'un viaggio da Constantinopoli in Polonia con ima relazione delle rovine cU Troja". The hardships of this journey shattered his health, yet we find him shortly after (1762) employed at Rome in various practical works, such as the draining of the Pontine marshes. In 1764 he accepted the appointment of professor of mathematics at the L'niversity of Pavia (Ticinum). At the same time Father La Grange, the former assist- ant of Father Pezenas of the Observatory of Marseilles, was invited by the Jesuits of Milan to erect an ob- servatory at the large college of Brera. He was able to avail liimself of the technical skill of Boscovich in carrj-ing out his commission and it may be ques- tioned to which of the two belongs the greater credit in the foimding of this observatory which, even in our own time, with that of the Collegio Romano, is among the most prominent of Italy. It was Bosco- ^^ch who selected the south-east corner of the college as a site for the observatory and worked out the com- plete plans, including the reinforcements and the necessary remodelling for the structure. Building operations were immei-liately begun and in the fol- lowing year, 1765, a large room for the mural quad- rants and meridian instnmients, another for the smaller instruments, and a broad terrace, with several revolving domes to contain the sextants and equa- torials, were completed. Such was the stability of the observatory that the new 18-inch glass of Scliiapa- relli could be mounted in it although a cylindrical dome with a diameter of 13 yards, 4 inches now takes the place of the octagonal hall of Boscovich. The London Academy proposed to send Boscovich in charge of a scientific expedition to California to observe the transit of Venus in 1769 but, unfortu- nately, the opposition manifested everjT\'liere to the Society of Jesus and leading finally to its suppression, made this impossible. He continued, however, to give his services to the Milan Observatory for wliose further development he was able to obtain no in- considerable sums of money. In particular the ad- justment of the instrmncnts engaged his attention, a subject about which he has left several papers. But as his elaborate plans received only partial sup- port from his superiors and patrons, he thought seriously in 1772 of severing his connexion with the observatory and, in fact, in the same year. Father La Grange was placed in complete charge of the new institution. Boscovich was to become professor at the University of Pisa, but Louis XV gained his services and invited him to Paris where a new office, Director cf Optics for the Marine — d'optique au service de la Marine — T\nth a salary of 8,000 francs, was created for him. He retained this position until 1783 when he returned to Italy to supervise the