(FELIX), a distinguished physiologist and experimental philosopher, was born 15th April 1730, at Pomarolo, a little town in the Tyrol.

He began his studies at the neighbouring city of Roveredo, and continued them in the schools of Verona and Parma, and afterwards in the universities of Padua and Bologna. He then visited Rome, and went to Florence, where he obtained from the Emperor Francis I. who was at that time Grand Duke of Tuscany, the appointment of Professor of Philosophy at Pisa; but the Grand Duke Peter Leopold, who was also afterwards Emperor, invited him to settle at Florence, and gave him an establishment connected with his household, as Fisico or naturalist, and as Director of the Cabinet of Natural History, which was afterwards rendered, by his exertions, one of the principal ornaments of the city of Florence.

Fontana became the author of many well known works on physiology, natural philosophy, and chemistry. In 1757, he was engaged in an investigation, tending to confirm the doctrines of Haller respecting the irritability of the muscles, considered as a distinct quality inherent in those organs. Haller has published several of his letters as a part of his own Mémoires sur les parties sensibles et irritable; and the subject has afforded to Fontana the materials of several successive essays. 1. De irritabilitatis legibus nunc primum sancitis. Atti di Sienna, Vol. III. p. 209. (1767.) 2. Ricerche filosofiche sopra la fisica animale. 4. Flor. 1775. This volume contains only the Essay on the Laws of Irritability, stating, first, the general outline of the doctrine, then entering into the different intensity of the property of irritability, and its loss by exhaustion or by inactivity, and discussing the action of the heart, and the peculiarities of the death occasioned by electricity. 3. Another link of the same chain of investigation is found in the earlier publication De' moti dell' iride. 8. Lucca, 1765; showing that the contraction of the pupil depends on the effect of light falling on the retina, and not on the iris itself, and establishing an analogy between the motions of the uvea, and the semivoluntary actions of the muscles of respiration. 4. One of the most important of Fontana's works is his Ricerche fisiche sopra 'l veleno della vipera. 8. Lucca, 1767; containing an immense multitude of experiments, calculated to show that the poison of the viper acts by mixing with the blood, and destroying the irritability of the muscles to which it is conveyed, but that the bite of the European viper, though fatal to small animals, is scarcely ever capable of producing any immediately dangerous effects on the human frame. 5. The same matter was republished, with many additions, in the Traité sur le venin de la vipère, sur les poisons Américains, sur le laurier-cerise, et sur quelques autres poisons. 2 v. 4. Flor. 1781. Germ. Berl. 1787, together with some observations on the primitive structure of the animal body, experiments on the reproduction of the nerves, and remarks on the anatomy of the eye. 6. In 1766, our author published an essay entitled Nuove osservazioni sopra i globetti rossi del sangue. 8. Lucca; contesting the assertions which had lately been advanced by Della Torre, respecting the complicated structure and changes of form of the globules of the blood. 8. In the next year Osservazioni sopra la ruggine del grano. 8. Lucca, 1767, describing an animalcule like an eel, to which he attributes the rust of coin, but which has not always been found by subsequent observers in similar cases, perhaps for want of an accurate distinction of the disease intended. 9. There is also a Lettre sur l'ergot. Journ. Phys. VII. p. 42. 10. The Lettera sopra le Idatidi e le Tenie. Opuscoli Scelti. VI. p. 108. Milan, 1783, contains an account of the hydrids which produce the symptoms of vertigo in sheep. 12. A Lettre à M. ***, Journ. Phys. VII. p. 285, contains some remarks on the circulation of the sap in plants. 13. In an essay, Sur le Tremella, Journ. Phys. VII. p. 47, a zoophyte of a green colour, described by Adanson and others as a plant, is shown to consist of a multitude of little animals in continual motion.

14. Mr Fontana entered also very minutely, but with more industry than accuracy or closeness of reasoning, into the chemical novelties which occupied so much attention throughout Europe in the latter half of the last century. He seems, however, to have had the merit of first applying the discoveries of Priestley respecting the effects of the nitric oxyd to the examination of the qualities of the atmosphere, by means of the eudiometer, which is the subject of his Descrizione e usi di alcuni strumenti per misurar la salubrità dell’ aria, 8. Flor. 1774, 4to, 1775, and is further illustrated in his (15.) Recherches physiques sur la nature de l’air dephlogistiqué et de l’air nitreux. 8. Par. 1776. He also observed the remarkable property that charcoal possesses, of absorbing several times its bulk of different gases. 16. In the Ricerche fisiche sopra l’aria fissa, 4. Flor. 1775, he is by no means equally fortunate, having fancied that the acidity of the fixed air is not essential to it, but accidentally derived from the stronger acid employed in expelling it from the earth or alkali. 17. The Philosophical Transactions for 1779, p. 187, contain his Experiments and Observations on the Inflammable Air breathed by various Animals, consisting of a repetition of Scheele’s attempt to breathe hydrogen gas, which did not always create a sensation of immediate uneasiness, though it was sometimes productive of alarming consequences. 18. In the same volume, p. 432, we find an interesting Account of the Airs extracted from different kinds of Waters, with Thoughts on the Salubrity of the Air at different places, showing that the air afforded by water is very different under different circumstances, but that the quality of the atmosphere itself scarcely ever exhibits any variations which can be rendered sensible by chemical tests.

19. To the Memoirs of the Italian Society Fontana contributed several short essays; the first, entitled Principi generali della solidità e della fluidità dei corpi, Vol. I. p. 89, Verona, 1782; containing the prevalent theories of the day respecting the change in the forms of aggregation of the same substance, together with experiments on the elasticity of different gases. 20. The second is a collection of definitions, entitled Sopra la luce, la fiamma, il calore e il flogisto, p. 104, characterizing these supposed elementary principles according to the ideas of Bergman, Scheele, and others. 21. In a later volume, V. p. 581 (1790), we find a Lettera del Cavaliere F. Fontana al Sign. de Morveau, in which it is conjectured that inflammable air may be a compound of phlogiston and water, and it is observed that the white crusts of flints contain as great a proportion of pure silica as their internal parts. Our author remarks, however, that his attention had of late been much distracted from chemical pursuits by the attention required for the completion of his collection of wax models of anatomical subjects, and for the duplicates which he was preparing for the cabinet of Vienna at the request of the emperor. At a subsequent period, another series of copies of these models was ordered by Bonaparte to be sent to Paris; but it was there judged inferior to the preparations already existing in the Ecole de Medecine, which had been made under the direction of Laumonier, and Fontana’s collection was sent to the university of Montpellier. He was latterly engaged for some time in the preparation of a colossal model of a man, built up anatomically of all his component parts, which were accurately represented in wood; but this elaborate design was never completed.

22. He was also the author of a few other chemical and mineralogical papers of less importance, for instance of an Analyse de la Malachite, Journ. Phys. XI. p. 509; and, 23. A Lettre sur du vitriol de Magnésie trouvé dans des carrières de gypse, en Piémont, Journ. Phys. XXXIII. p. 309. 24. His last work is entitled Principes raisonnés de la génération. He was also meditating an essay on the revivification of animals; but he did not live to complete it. A collection of his works, translated into French by Gibelin, was published at Paris in 1785, entitled Observations Physiques et Chimiques.

Fontana had become acquainted with a great number of contemporary men of science, by having travelled in various parts of Europe, for the purpose of enriching the cabinet of which he was superintendent; the same official situation brought him into contact with all foreigners of distinction who passed through Florence in their travels; and he seems to have enjoyed a more extensive reputation than many philosophers of deeper research and more irresistible penetration. He wore the habit of an ecclesiastic, and was not uncommonly called Abbé; he was well received in the best societies, though his manners are said to have been sometimes a little at variance with the dress which he adopted. He was treated with great respect by the French generals, when they took possession of Tuscany in 1799, and hence he became the object of some suspicion upon the return of the Austrians, especially with the insurgents of Arezzo, who preceded them, and by whom he was for a short time imprisoned. His last illness was occasioned by an accidental fall in the street, on the 11th January 1805, and he died the 9th March 1806, at the age of seventy-five. He was buried in the church of the Holy Cross, not far from the tomb of Galileo. His Eloge was pronounced by Professor Mangili in the university of Pavia, the 12th November 1812. (Cuvier, in Biographie Universelle, Vol. XV. 8. Par. 1816.)

(Gregory), a profound mathematician and natural philosopher, younger brother of Felix Fontana, was born at Villa de Nogarola 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 Scuole 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 Macenas 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' Accademia 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 Physicomical 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. Motire, 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, Sienna, 1779. 59. Compendio di un corso di Fisica del Sign. G. Atwood, Pavia, 1781. 60. Saggio sopra i principi