BOSCOVICH, ROGER JOSEPH

BOSCOVICH, ROGER JOSEPH, was born on the 18th of May 1711, at Ragusa, a sea-port on the coast of the Adriatic, and capital of a small republic of the same name, then under the protection of the Turks and the Venetians. It does not appear that our author gave any tokens of superior genius till he was sent to learn grammar and philosophy in the schools of the Jesuits, who were at that time the principal teachers in Ragusa, and indeed throughout all Italy. Amongst these shrewd observers his docility and obedience were sufficient to mark him out as a person likely to attain future eminence, and consequently to procure him particular attention. In his fifteenth year, after he had gone through the ordinary course of education, and when it was necessary to decide as to his future pursuits, application was made for his admission into the order; and, for the reasons just mentioned, this was readily complied with, and the subject of the present notice sent to Rome in the year 1725. On his arrival in the Eternal City he entered on his noviciate for admission into the order; but here his studies changed their character and direction, although they were still pursued with diligence. Christian morality, with the rules and constitutions of the order, claimed his attention for two years; after which he was instructed in rhetoric, and became well versed in general literature, particularly Latin poetry, which at that time was very much cultivated.

From the noviciate he was sent to the Roman college to study mathematics and physics; and it was in these sciences that his genius and abilities shone forth so conspicuously, and procured him the admiration of his super-

Boscovich. In the course of three years he was able to give private lessons in the mathematics; and he was then exempted from the operation of a law, by which the novices were bound to teach Latin and the belles-lettres for five years before they commenced the study of theology. This exemption was in consequence of his great predilection for the mathematics, of which he was soon afterwards made public professor. For this professorship he was eminently qualified, as, besides a thorough knowledge of all the modern productions in the science, he had acquired a classical severity of demonstration by studying the works of the ancient geometers; yet he conjoined with an obliging accommodation of his own habits to the deficiencies of his pupils, and for their benefit composed elementary treatises on arithmetic, algebra, geometry, and trigonometry. But notwithstanding the arduous duties of his situation, he found time to instruct and enlighten more than boys; for about this period he formed some of those refined and original notions which were destined to grow up into the system that afterwards became so celebrated. The animating spirit of discovery and invention led him to consider every portion of physical science; and indeed so versatile and vigorous was his mind, that we should be at a loss to specify any one portion which, within a few years, it did not comprehend, elucidate, and advance. In confirmation of this it will be sufficient to present our readers with an enumeration of the principal subjects to which he turned his attention, and concerning which he published dissertations while he continued in the professorship. These were, the transit of Mercury over the sun, the spots in the sun, the aurora borealis, the construction of spherical trigonometry, the figure of the earth, a new telescope to determine celestial objects, the ancient arguments for the rotundity of the earth, oscillating circles; on infinites and infinitely small quantities, the motion of bodies in unresisting spaces, the aberration of the fixed stars, the inequalities in terrestrial gravity; on astronomy, on the limits of certainty in astronomical observations; on the solid of greatest attraction, the cycloid, the logistic curve lines, the vires, the comets, light, the tides, the rainbow, the calculation of fractions, the centre of gravity, the moon's atmosphere, the law of continuity, lenses and dioptrical telescopes, the objective micrometer, and the divisibility of matter. Some of these are short, but all of them contain curious and valuable matter. It is only by perusing them that we are able to discover the gradual progress of his mind, and to understand the manner in which he arrived at that theory of natural philosophy which is now known by his name.

About this time a taste for philosophical poetry was very prevalent amongst the learned, and some of Boscovich's acquaintances had laboured in it with success. Of these we may mention Father Noceti, who wrote on the rainbow and the aurora borealis, and Benedict Stay, whose poems on the philosophy of Descartes, and on the more modern philosophy, are considered as excellent examples of Latin composition. Boscovich published the works of both with annotations and supplements, in which a splendid fund of information and learning is displayed.

By such undertakings his fame was widely diffused, and he became an object of general admiration. The learned societies of many countries in Europe conferred on him unsolicited honours, and several foreign princes invited him to their courts. His opinions on various subjects of civil architecture, topography, and hydrodynamics, were solicited by Pope Benedict XIV., John V. of Portugal, and others. These applications necessarily required his presence in different states of Europe, where he never failed to enhance his reputation, and often terminated dis-

putes which, but for his judicious interference, might have had disagreeable consequences.

He was employed to correct the maps of the papal dominions, and to measure a degree of the meridian passing through them. In this operation he was assisted by an English jesuit named Christopher Maire. An account of their expedition was printed at Rome and Paris, and is interspersed with some curious anecdotes concerning the opinions which the peasants of the Apennines, formed of them, and the operations which they had to perform; but it is chiefly valuable on account of the detail which is given of their observations.

In the year 1757 he was sent to Vienna by the republic of Lucca, to settle some differences which had arisen concerning the draining of a lake, in which the grand duke of Tuscany, the emperor Francis I., and that republic, were concerned; and it was after he had succeeded in the object of his mission to that city that he published there his Theoria Philosophiae Naturalis in 1758.

Another occasion for his mediating powers soon presented itself, and more nearly interested him, as it concerned his native city of Ragusa. The British government having suspected that some ships of war had been fitted out in that port for the service of France, and that its neutrality had thus been infringed, this suspicion alarmed the senate of Ragusa, and required speedy removal, more especially as the consequences might have been extremely prejudicial to their commerce. Boscovich, who had often been successful in similar missions for other powers, appeared to them the fittest person to be intrusted with this. Accordingly, having been nominated by his countrymen, he repaired to London, where he effected the object of his mission with honour to himself and satisfaction to his native state. He visited the Royal Society, which received him with distinguished marks of respect; and he soon afterwards complimented it with an excellent Latin poem on the solar and lunar eclipses. This was in the year 1760. Boscovich was invited by the Royal Society to be of the party of their members about to proceed to America in order to observe the transit of Venus over the sun's disc. But the nature of his embassy, and the necessity of returning home, prevented his accepting the invitation. Soon after his return from this embassy, he was appointed by the senate of Milan to the mathematical chair in the university of Pavia, with the superintendence of the observatory of the royal college of Brera. He continued in this situation for six years, when the empress queen appointed him professor of astronomy and optics in the Palatine schools of Milan, and also requested that he would continue his attention to the observatory. This he expected to prove the most agreeable part of his life. Admired by the learned, beloved by his friends, and having an adequate income, with a sound and vigorous constitution, he promised to himself happy because useful days, in the tranquil cultivation of the sciences. But a cloud long impending now burst over his head, in the edict for the abolition of his order, which took place in the year 1773. No exemption from the edict could be procured; all who held offices were dismissed; and Boscovich sought refuge in the city of Paris. Thither indeed he was invited by Turgot, through whose means he was made one of the directors of optics for the sea service, and received a pension; but it would seem that his situation proved disagreeable to him; nor is this to be wondered at, considering the peculiar circumstances which had induced him to take up his residence in the French capital. He remained there, however, for ten years, on the expiry of which he set out for Bassano, in the republic of Venice, and there published, in five vo-

Boscovich, lumes quarto, a collection of the works which he had completed in Paris. The following is a pretty accurate enumeration of their contents: A new instrument for determining the refracting and diverging forces of diaphanous bodies; a demonstration of the falsehood of the Newtonian analogy between light and sound; the algebraic formulae regarding the foci of lenses, and their applications for calculating the sphericity of those which are to be used in achromatic telescopes; the corrections to be made in ocular lenses, and the error of the sphericity of certain glasses; the causes which hinder the exact union of the solar rays by means of the great burning glasses, and the determination of the loss arising from it; the method of determining the different velocities of light passing through different media by means of two dioptic telescopes, one common, the other of a new kind, containing water between the objective glass and the place of the image; a new kind of objective micrometers; the defects and inutility of a dioptic telescope proposed and made at Paris, which gives two images of the same object, the one direct, the other inverse, with two contrary motions of movable objects; masses floating in the atmosphere, as hail of an extraordinary size, seen on the sun with the telescope, and resembling spots; the astronomical refractions, with various methods for determining them; different methods for determining the orbits of comets and of the new planet, with copious applications of these doctrines to other astronomical subjects, and still more generally to geometry and to the science of calculation; the errors, rectifications, and use of quadrants, sextants, astronomical sectors, the meridian line, telescopes called transit instruments, the meridian, and the parallactic machine; the trigonometrical differential formulae, which are of so much use in astronomy; the use of the micrometrical rhombus, extended to any oblique position whatsoever; the error arising from refractions in using the astronomical ring for a sun-dial, and the correction to be made; the appearing and the disappearing of Saturn's ring; methods of determining the rotation of the sun by means of the spots; the greatest exactness possible in determining the length of a pendulum oscillating every second of mean time by the comparison of terrestrial and celestial gravity; a compend of astronomy for the use of the marine, containing the elements of the heavenly motions, and of the astronomical instruments, to be explained to a prince in the course of one month; a method for determining the altitudes of the poles with the greatest exactness, by means of a gnomon alone, where other instruments are not to be had; the determination of the illuminated edge of the moon to be observed on the meridian; a method of using the retrograde return of Venus to the same longitude, for determining the less certain elements of her orbit; a method for correcting the elements of a comet, of which the longitude of the node is given, and the inclination of the orbit has been nearly found; another method for the same purpose, and for finding the elliptical orbit, when the parabolic one does not agree with observation; a method for correcting the elements of a planet by three observations; the projection of an orbit inclined in the plane of the ecliptic; the projection of an orbit inclined in any other plane; the calculation of the aberration of the stars, arising from the successive propagation of light; and some beautiful theorems belonging to triangles, which are of great use in astronomy, reduced to the most simple demonstrations.

After the publication of these works, our author quitted Bassano, and went to Rome to visit the companions of his youth. From Rome he proceeded to Milan, where he revised some of his own works, and prepared for publication the two last volumes of Stay's poems. His death

took place on the 13th of February 1787, in the seventy-sixth year of his age. Boshuanas.

Besides the different works above mentioned, Boscovich wrote several others on various subjects, as on the project of turning the navigation to Rome from Fiumicino to Maccarese; on two torrents in the territory of Perugia; on the bulwarks of the river Ponaro; on the river Sidone in the territory of Placentia; on the bulwarks of the Po; on the harbours of Ancona, of Rimini, of Magna Vacca, and Savona; besides some others, almost all of which were printed. For an account of the system developed in the Theoria Philosophiae Naturalis, see the article PHYSICS.