printing of his as yet unpublished works in five volumes, for it was not easy to find a suitable pub- lisher in France for books \\Titten in Latin. In 1785 there appeared at Bassano, "Rogerii Josephi Bosco- vich opera pertinentia ad opticam et astronomiam ... in quinque tomos distributa", the last im- portant work from the pen of this active man, who, after its completion, retired for a time to the mon- astery- of the monks of Vallombrosa. He returned to Milan with new plans, but death shortly overtook him at the age of seventy-six, delivering him from a severe malady which was accompanied by temporary mental derangement. He was buried in the church of Santa Maria Potlone.
Boscovich, by his rare endowments of mind and the active use which he made of his talents, was pre- eminent among the scholars of his time. His merits were recognized by learned societies and universities, and by popes and princes who honoured him and bestowed favours upon him. He was recognized as a gifted teacher, an accomplished leader in scientific enterprises, an inventor of important instruments which are still employed (such as the ring-micrometer, etc.'), and as a pioneer in developing new theories. All this, however, did not fail to excite envy against him, particularly during the later years of his life in France, where men like d'Alembert and Condorcet reluctantly saw the homage paid to the former Jesuit, and that, too, at a time when so many frivo- lous charges were being made against his lately sup- pressed order. This hostility was further increased by various controversies which resulted in differ- ences of opinion, such as the contention between Boscovich and Rochon regarding priority in the in- vention of the rock crystal pri.smatic micrometer. (Cf. Delambre, Histoire de I'Astronomie du XVII1'= siecle, p. 645.) The invention of the ring-micrometer just mentioned, which Boscovich describes in his memoir "De novo telescopii usu ad oljjecta coelestia determinanda" (Rome, 1739), has been ascribed without re;i.son by some to the Dutch natural phi- losopher Huygens. The chief advantage of the simple measuring instrument devised by Boscovich consists in its not requiring any artificial illumination of the field of the telescope. This makes it useful in observing faint objects, as its inventor expressly points out in connexion wth the comet of 1739. The novel views of Boscovich in the domain of natu- ral philosophy have not, up to the present time, passed uncliallenged, even on the part of Catholic scholars. Against his theory of the constitution of matter the objection has teen raised that an in- admissible actio in uislans is inevitable in the mutual actions of the elementary points of which material bodies are supposed to be composed. The theory therefore leads to Occasionalism. Acknowledgment must, however, be made of the suggest iveness of Boscovich's work in our own day, and the germs of many of the conclusions of modern physics may be found in it. His illustrious successor at the Observa- tory' of the Collegio Romano, Father Angelo Secchi, in liis "I'niti delle forze fisiche", has in many re- spects followed in his footsteps, and in fact the cosmological views held by many later natural phi- lo.sophers furnish unequivocal proof of the influence of the theories maintained by Boscovich.
Among his many .smaller works (for full list cf. Somraervogcl, cited below) the following deserve special attention: "De annuls stellarum fixarum aberrationlbus" (Rome, 1742); "De orbitis come- tarum determinandis ope trium observationum parum a sc invicem remotarum" (Paris, 1774); "De recentibns com])crtis pertinentibus ad perficiendam dioptricam" (17()7). His chief works, however, are: (1) "De litteraria expeditione per Pontificiam di- tionem" (1755); (2) "Theoria philosophia; natiiralis" (1758); (3) " Opera pertinentia ad opticam et As- II.— 44
tronomiam maxima ex parte nova et omnia hucusque inedita" (1785). The second was published in Vienna 1758-59, in Venice, 1763, and again in Vienna in 1764. The last-named work was subjected to an exhaustive criticism by Delambre, by no means a friend of the Jesuits. He closes with these words: "Boscovich in general manifests a preference for graphical methods in the use of which he gives evi- dence of great skill. In his whole work he shows him- self a teaclier who prefers to lecture rather than to lose himself in speculations".
The most extended biographical account of Boscovich may be found in Vit'V Italorum, Auctore Angela Fabronio, Acadeniur Pisaiur curatore (Pisa, 17S9), XIV; cf. also So-mmervogel, Bibl. de la c. de J. (Brussels. 1890). I, col. 1S2S-S0. For shorter accounts cf. Zamagn.\ (Ragusa. 1787); Lalande (Paris, 1792); RiccA (Milan, 1789); Bagamonti (Ragusa. 1789); BizzARRo (Venice. 1817); Galleria di Ragusani illustri (Ragusa. 1841); Vaccolini in Giomale arcadieo (1842), XCII. 174.
Bosio, Antonio, known as "The Columbus of the Catacombs", b. in the island of Malta about the year 1576; d. 1629. While still a boy he was sent to Rome and placed in charge of an uncle who repre- sented the Knights of Malta in the Eternal City. In the Roman schools he studied literature, philosophy, and jurisprudence, but at the age of eighteen he gave up his legal studies and for the remaining tliirty-six years of liis life all his time was devoted to archaeologi- cal work in the Roman catacombs. The accidental discovery, in 1578, of an ancient subterranean ceine- tery on the Via Salaria had for the moment attracted general attention in Rome. Few, however, realized the importance of the discovery, and, with the ex- ception of three foreign scholars, Ciacconio, De Winghe, and L'Heureux, no one seriously thought of pursuing further investigations. It was reserved for Bosio to begin the systematic exploration of sub- terranean Rome and thus to become the foimder of the science of Christian archa-ologj'. The yoimg explorer from the beginning realized that in early Christian literature he would find an indispensable ally, and accordingly he began to study the .A.cts of the Martyrs and of the Councils, the writings of the Greek und the Latin Fathers, and in fact every species of document that might help to throw light on the obscurities of his subject. An idea of the vast scope of his reading may be obtained from the two great tomes of his manuscript notes in the Vallicelliana librarj- at Rome, each of which contains about a thousand pages in folio.
The Uterar ,- labours of Bosio accoimt for only half of Ills time; the other half was consumed in systematic efforts to utilize the information derived from his read- ing for Ills particular object. Thus, for example, after he had collected all the data possible relative to the location of a catacomb on one of the great roads leading from Rome, Bosio would betake himself to the place indicated, and go over everj- inch of ground carefully in the hope of discovering a for- gotten stairway, or luminarium. , of a cemetery. If fortime crowned liis investigations with success, he would then descend to the subterranean abode of the long-forgotten dead, and, sometimes at the imminent danger of being lost in the labyrinth of galleries, commence his explorations. The great work achieved by Bosio was almost unknown till the pubHcation three years after his death of liis "Roma Sotterranea". The folio volume was brought out under the patronage of the Knights of j\lalta, by the Oratorian Severano, who had been entrusted with its editorship by Cardinal Francesco Barberini. Its full title is "Roma Sotterranea, opera postuma di .\ntonlo Bosio Romano, antiquario ecclcsiastico singolare de' suoi tempi. Compita, disposta, et accresciuta dal M. R. P. Giovanni Severani da S. Severino" (Rome, 1632). The great merit of the new pubUcation was at once recognized. A Latin