FONTANA (GREGORY), a profound mathematician and natural philosopher, younger brother of Felix Fontana, was born at Villa de Nogaroia near Roveredo, the 7th December 1735.
He received the first rudiments of his education at Roveredo, and continued his studies at Rome, where he entered into the Scolae Pie, and soon distinguished himself by his talents and assiduity. He was entrusted with the care of a part of the public instruc-
tion in the school called the Collegio Nazareno, and was soon afterwards sent as a professor to Sinigaglia. It was here that he formed an intimacy with the Marquis Fagnani, whose example and assistance contributed very much to the advancement of his mathematical studies, to which he very soon in great measure confined his attention. He was then removed by his superiors to Bologna; but his co-operation was found more necessary for the Pious Schools, which had lately been established, at Milan; and he here obtained the patronage and friendship of the Count de Firmian, the Mæcenas of the day, who greatly encouraged the publication of his first works. From these works he acquired so much credit, that he was summoned, in 1763, to occupy the chair of logic and metaphysics in the university of Pavia, and he was appointed by Firmian director of the public library, which he founded about the same time for the university. Two years afterwards, he was advanced to the professorship of the higher mathematics, which was become vacant by the death of the celebrated Boscovich, and he filled this situation with high reputation for thirty years. He was the author of a great variety of memoirs, and did not even disdain the labour of a translator, when he thought that it could be useful to his pupils or his countrymen; but he never engaged in any single original work of great extent; for notwithstanding his habitual industry, his disposition was too volatile to allow him to confine himself long enough to any one object to effect any striking innovation in the complexion of the sciences which he cultivated. He was assiduous in the duties of his professorship, and his personal intercourse with society was extremely limited, though his correspondence with men of science was extensive. He was in the habit of writing many notes in the margin of the books that he read, and the volumes which composed his library acquired a double value from this circumstance. In April 1795, he was elected a foreign Member of the Royal Society of London. About this time his health began to decline, and his physicians considered him as having suffered from too great application to his studies. In 1796, he received great marks of respect from Bonaparte, then commanding the French army in Italy, and he was made a member of the legislative body of the newly erected Cisalpine republic. In 1800, having resigned the professorship at Pavia, he came to Milan, and was afterwards nominated one of the Electoral College of the Dotti. He was still occupied in a variety of literary pursuits, when he was attacked by a violent fever, which caused his death at Milan, the 24th August 1803. He left his manuscripts to his brother Felix, who died soon after him. An unmarried sister survived them both, and inherited the little property of her brothers, which was soon exhausted, and she was reduced to the extremity of distress. At last, finding no protection in a country to which her family had done so much honour, she became desperate, and drowned herself in the canal of Milan.
1—7. Father Fontana's principal publications were, first, seven Academical dissertations on various departments of mathematical and mechanical science, among which are the Analyseos Sublimioris Opuscula.
4. Ven. 1763, and the Memorie Matematiche, 4. Pavia, 1796. 8—23. There are sixteen short memoirs in the Atti dell' Academia di Siena. Their subjects are, 8. Astronomical Problems, Vol. V. 1774, p. 55. 9. Theorems relating to the Integral Calculus, p. 69. 10. Remarks on Incommensurable Quantities, p. 71. 11. On the Quantity of Air in the Atmosphere, p. 76. 12. On the Area of a Spherical Triangle, p. 83. 13. On the Binomial Theorem, p. 88. 14. On Accelerated Motion, p. 92. 15. On Projectiles, p. 97. 16. On a Phenomenon of Vision, p. 103, attempting to explain the comparative brightness of an object seen by one and by both eyes. 17. On the Effect of the Solar and Lunar Attraction upon the Height of the Barometer, p. 116. 18. On the Mathematical Discoveries of Cardani and Cavalieri. 19. An Essay on the Gradual Renewal of the Blood of an Animal, and on the Principles of Compound Interest and Discount, Vol. V. 1781, p. 161. 20. On the Axis of Equilibrium, p. 173. 21. On Curves described by the Centre of Gravity, p. 177. 22. On the Centres of Gravity of Hyperbolic Spaces or Figures, p. 180. 23. On Indefinite Equations, and on the Method of Indeterminates, p. 184.
24—40. There are also a great variety of papers in the Memorie della Società Italiana delle Scienze. Among them we have, 24. An Essay on the Descent of a Body, on a Convex Surface, Vol. I. Verona, 1782, p. 94. 25. Remarks on the Measurement of Light, p. 111, in which the elegant experiments of Lambert are applied to the explanation of the uniformity of the light of the sun's disc; an essay which would have saved a great Parisian astronomer some useless labour and calculation, if it had excited his attention. 26. On the Logarithms of Negative Quantities, p. 183. 27. On the Equation of a Curve on Two False Theorems, and on Harmonic Series, Vol. II. 1784, p. 423. 28. On the Pressure of Fluids, p. 192. 29. On Centrifugal Force, p. 325. 30. On Series, p. 326. 31. On Converging Series formed by the Products of the odd and even numbers, Vol. III. 1786, p. 174. 31. Analytical Researches on Refraction, on Perpetual Motion, on the Integration of Equations, on Collision, on the Resolution of Forces, and on the Pressure of Beams. There is also an Essay on Buffon's combination of Mirrors, and another on the Quantity of Light Reflected by a Mirror in a Given Direction. 41—51. Five papers of G. Fontana appear in the Memoirs of the Academy of Turin for 1804, five in the Biblioteca Fisica d'Europa, and four in the Physicomedical Journal of Pavia. Of these one of the most interesting relates to the Magnifying Power of Telescopes, and is reprinted in the XVth Volume of the Raccolta di Opuscoli, published at Milan.
55. Of his translations, the principal are La Dottrina degli azzardi di A. Moivre, Pavia, 1776, with additions, said to be a piratical publication. 56. Saggio di una difesa della Divina Revelazione, di L. Eulero, Pavia, 1777. 57. Dissertazione di Mosheim sopra l'opera di Origene contro Celso, Pavia, 1778, with notes. 58. The Hydrodynamics, and other Mathematical Works of Bossut, Siena, 1779. 59. Compendio di un corso di Fisica del Sign. G. Atwood, Pavia, 1781. 60. Saggio sopra i principi
della composizione storica, del Sign. Hill, Pavia, 1789, with an appendix. 61. Discorso Preliminare agli atti della Società Linneana di Londra, del Sign. J. O. Smith, Pavia, 1792. 62. Sermone sul Martirio del re Carlo I. dal Dr G. Swift, Pavia, 1798. 63.
L'Esempio della Francia, avviso e specchio all' Inghilterra, di A. Young. Pavia, 1794.
(GUILLOIN in Biographie Universelle, Vol. XV. S. Par. 1816.) (T. U.)