BORELLI, JOUR ALPIIONSUS, a celebrated Ita lian physician and anatomist; was born at Castel Nuovo, in the kingdom of Naples, on the 28th of January 1608. Having been sent to finish his education at Rome, he made rapid progress under the care of eastern, and acquired such a reputation for his abi lities, that he was invited to teach mathematics at Messina in Sicily. In 1647 and 1648, a malignant fever having broken out in that island, and committed dreadful ravages, Borelli paid particular attention to the disease, and published a treatise upon it at Co senza, entitled, Delle ragioni delle febri maligni di Sicilia, 12mo, 1649. From Messina he went to Pisa, where he was appointed professor of philosophy and mathematics, an office which he filled with great suc cess. The fame of his talents had reached the ears of the Grand Duke Ferdinand, and of Prince Leopold, through whose influence he was honoured with a seat in the Academy del Cimento. About this time he be gan to employ his mathematical knowledge in ex plaining the functions of the animal ccconomy; and we accordingly find, that between the years 1659 and 1664, he wrote numerous letters to Malpighi upon that subject, which were afterwards published in the posthumous works of that learned anatomist.
Having engaged in the revolt of Messina, he was obliged to quit Sicily and retire to Rome, where he lived under the patronage of Queen Christina, who was at that time resident in the capital of Italy. The liberality of the Swedish queen, however, does not seem to have been of great extent, as we find Bo relli under the necessity of teaching mathematics in the pious schools in the convent of St Pantalion, where he died of a pleurisy on the 31st Dccenibcr 1679, in the 72d year of his age.
Borclli carried on a correspondence with some of the leading philosophers of his age, particularly with Mr John Collins, Mr Oldenburgh; Dr Wallis, Mr Boyle, and Malpighi, and as held in high estima tion among his contemporaries.
His principal writings are : .1. Delle ragioni dellc febri maligni di Sicilia. Cosenza, 1649, 12mo.
2. Della cause delle febri maligni. Pisa, 1658, 4to.
3. Apollonii Pergxi Conicorum, lib. v. vi. et vii. Florent. 1661, fol.
4. De Renum usu judicium, accompanied by Bel lini's treatise De structure Renum. Strasburg, 1664, Svo.
5. Theorize Meeticorum Planetarum ex causis Physicis deducts'. Florent. 1666, 4to.
6. De vi Percussionis. Bologna, 1667, 4to.
7. Euclides Restitutus. Pisa, 1668, 4to.
8. Osservatione intorno alla vista in eguali degli Occi, published in the Journal of Rome for 1669.
9. De motionibus naturalibus de Gravitate pen dentibus. Regio Julio, 1670, 4to.
10. Meteorologia,./Etnea. Regio Julio, 1670, 4to. Borelli having been present at the formidable and destructive eruption in 1669, drew up an account of it at the desire of the Royal Society of London, who printed it in their Transactions.
11. Osservatione dell' Ecclipi Luuari 11 Gennaro 1675, published in the Journal of Rome for 1675, p. 34.
12. Elementa Conica Apollonii Pergmi, et Archi medis Opera, nova et breviori Methodo demonstrata. This work was printed at Rome in 1679 in 12mo, at the end of the 3d edition of his Euclides Restitutus.
13. De motu Animalium. This work was pub lished after Borelli's death. The first part appeared in 1680, and the second in 1681. A more correct edition was published at Leyden in 1685, along with John Bernoulli's Mathematical Meditations concern ing the Motion of the Muscles. Another edition ap peared at Leyden in 1686, under the care of Dr Brocn along with his two pieces, De vi Percussionis, and De Motionibus, &c.
The principal writings of Borelli are, his treatises on the Force of Percussion, and on the Motion of Animals. In the first of these works, he endeavours to demonstrate the proportion between the percus sive force, the motion or the velocity of the percus sion, and the resistance of the body struck ; and lie has not scrupled to say, that he has succeeded in de monstrating the nature, cause, properties, and effects of percussion. In this work he occasionally treats of gravity, magnetism, pendulums, and the tremor of bodies.
Borelli's treatise on the Motion of Animals, which was dedicated to Christina, Queen of Sweden, and printed at her expence, exhibits a fine application of the laws of statics to the motion of living beings. He supposes the muscular fibres to be vesicular, and their contraction to arise from the introduction of a portion of the nervous fluid, which mixes with the blood they contain, and by swelling them, shortens their length. He endeavours to measure the indi vidual and the collective power of the fibres which compose a muscle ; and he spews in what measure their power is varied, by the manlier in which the fibres are united with the tendons. Varignon and Dr Kcil have pointed out some errors in the calculations of Borelli ; but these are quite trifling, when com pared with the value and originality of this curious work. (Tr)