Many of these dissertations are extremely va luable; and the mathematical investigations which they contain, are distinguished by a clearness and elementary simplicity, which is very unusual in simi lar writings. When this labour was at an end, he spent some months in the convent of Valombrosa, in Tus cany, and afterwards went to Rome to revisit the companions of his early years. From Rome he went to Milan where he resumed his own studies, and amused himself with completing a new edition of his friend Benedict Stay's beautiful poem, entitled, Phi losophia Recentior, enriched with notes, and extend ed to ten books. The proposals, however, which he issued about this publication, did not Obtain him many subscribers ; and the limited-circulation which his works experienced, excited a dejection of spirits which his constitution was not able to bear. His leave of absence from Paris was now nearly expired, and he felt the greatest reluctance to return among the jealousies which surrounded him in the French capital. The conflict between his gratitude to the French king, and his own personal feelings, increa sed the melancholy which preyed upon his spirits, while a violent attack of the gout, and an inflamma tion in the lungs, completed his sufferings,.and drove him into a state of derangement.
Though this dreadful disorder proceeded, in some measure, from the bodily infirmities of Boscovich, yet it was chiefly owing to that secret anguish which sprung from the ingratitude of his countrymen, and the injustice of his cotemporaries. The visions of youthful ambition which the sanguine hopes of Bos covich had so early cheri shed ; the reverence which was paid to him at Rome, at Paris, and at London ; the great success of his writings; the high employ ments which he was afterwards called to fill, and the favour which was shewn to him by several of the princes of Europe,—the recollection of these better days, contributed to awaken more acute sensations at the neglect into which, in his old age, he had been permitted to fall. He felt that all his philosophy was insufficient to quiet the ferment of a proud spi rit, and he sought in religion for that support which it alone could bestow. Under the influence of these pious feelings, he regretted that he had spent so little time in the sacred duties of his profession, and that so much of his leisure had been occupied,by what he now considered, as the idle speculations of philoso phy. We are unwilling to believe, with one of the biographers 'of Boscovich, that these religious im pressions were the consequences of his mental deli rium. At no period of his life, did Boscovich ever hazard an opinion hostile to the noble sentiments which supported him in his latter days ; and the re verses and disappointments which embittered the close of his life, naturally carried his views beyond this troubled state of. existence, which a proud and
mortified .spirit is so willing to resign. Under the influence of these feelings, an imposthume burst in his breast, and he died on the 13th of February, 1787, in the 76th year of his age. He was interred without any kind of pomp, in the parish church of St Maria Pedore ; and the Senate of his native city. erected a monument to his memory, with the follow in inscription, composed by his friend Benedict Y: Boscovich was considerably above the middle size, of a strong make, and with a long and sallow visage. He possessed the virtues and the failings which spring from awarm temper ; and while the formerendeared him to his friends, the latter proved injurious only to himself. His numerous evidently the production of an original and inventive genius, and though com posed in a diffuse style, and with a redundancy of illus tration, are distinguished by n simplicity and perspi cuity which are seldom found in physical investiga tions.
The works of Boscovich which he published at. Bassano, contain the following Opuscules . VoL. t. Opusc. 1. De constructione et usu novi in strumenti maxime idonei ad determinandas vires re fractivas, et. distractivas substantiarum diaphanarum. Optisc. 2. Deductio formularum ad fn. cos lentium, cum earum applicatione ad calculandas sphxricitates, qua: adhibendi debent pro telescopiis acromaticis.
Vot.n. Opusc. 1. De correctionibus pertinentibus ad oculares, quibus accedit correctio solius erroris fi gurz sphxricz ivorum. Opusc. 2. De Lente ustoria potissimum ingenti. Opusc. 3. De mode de terminandi discrimen yelocitatis, quam habet lumen, dum percurrit diversa media, per dua telescopia diop, trica, alterum commune, alterum novi cujusdam ge neris. Opusc. 4. De novo genere microtnetri objec tivi. Opusc. 5. De telescopis exhibenti simul bi. nas imagines ejusdem objecti, alteram directam, i alteram inversam, cum earum motibus contrariis et zqualibus. Opusc. 6. De globulis nigris trans latis per discum sobs, cum Epistola Gallica ad ejus phenomeni observatorem. Opusc. 7. De refrac. tionibus astronomicis. Opusc. 8. De refractionibus astronomicis, et altitudine poli, determinandis per distantias apparentes binanim fixarum supra et in fra polum. Opusc. 9. Methodus determinandi re fractiones astronomical sine ulla suppositione physica, gum non videantur omnino ceria, ope .instrumenti ha bentis utilitatem generalem in Iota astronomia.
Vox,. tit. Opusc. 1. De la determination.de l'orbite d'une comete par trois observations pas eloignees en Opusc. 2. Sur la nouvelle planete.