Felice, a distinguished physiologist and experimental philosopher, born at Pomarolo, a little town in the Tyrol, on the 15th April 1730. 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 wrote many 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 afforded Fontana the materials of several successive essays—De Irritabilitatis legis nunc primum sanctis, Atti di Sienna, vol. iii., p. 209, 1767; 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 death occasioned by electricity. Another link of the same chain of investigation is found in the earlier publication, De moti dell'Iride, S. Lucca, 1765; showing that the contraction of the pupil depends on the Fontana, 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 semi-voluntary actions of the muscles of respiration. One of the most important of Fontana's works is his *Ricerche fisiche sopra l'Veneno della Vipera*, 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 *Vipera aspis*, though fatal to small animals, is scarcely ever capable of producing any immediately dangerous effects on the human frame. The same matter was republished with many additions in the *Traité sur le Venin de la Vipère, sur les Poisons Américains, sur le Laurier-cèdre, et sur quelques autres Poisons*, Berlin, 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. In 1766 our author published an essay entitled *Nuove Osservazioni sopra i globetti rossi del sangue*, Lucca; confuting the assertions which had lately been advanced by Della Torre respecting the complicated structure and changes of form of the globules of the blood. In the next year appeared *Osservazioni sopra la rugGINE del grano*, 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 accurate distinction. There is also a *Lettre sur l'Ergot*, *Journ. Phys.* vii., p. 42. The *Lettura sopra le Idiatridi e le Tenie, Opuscoli Scelti*, vii., p. 108, Milan, 1783, contains an account of the hydriads which produce the symptoms of vertigo in sheep. A *Lettre à M.***, Journ. Phys.* vii., p. 285, contains some remarks on the circulation of the sap in plants. 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.

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 oxide 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 *Recherches physiques sur la nature de l'air déphlogistique 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. 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. 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. 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.

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. 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. In a later volume, v. p. 581 (1790), we find a *Lettura del Cavaliere F. Fontana al Sign. de Moreau*, 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 Médecine, 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.

Fontana was also the author of a few other chemical and mineralogical papers of less importance. 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 died March 9th 1806, and was buried in the church of the Holy Cross, not far from the tomb of Galileo. (Cuvier, in *Biographie Universelle*, vol. xv. 8. Par., 1816.)

Fontana, Gregorio, a profound mathematician and natural philosopher, younger brother of Felice Fontana, was born at Villa de Nogrola, near Roveredo, on 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 instruction 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 a 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 there obtained the patronage and friendship of the Count de Firmian, the Macænas 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 1768 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 had become vacant by the death of the celebrated Boscorich, and he filled this situation with high reputation for thirty years. 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 Fontenelle army in Italy; and he was made a member of the legislative body of the newly erected Cisalpine republic. In 1800, Fontenelle, having resigned the professorship at Pavia, 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, on the 24th August 1803.

Fontana's principal publications were seven Academical Dissertations on various departments of mathematical and mechanical science; a great variety of papers in the Memoire della Societa Italiana delle Scienze; and numerous translations.