Newton, Isaac

NEWTON, ISAAC. - Scientist, b. at Woolsthorpe, county of Lincoln, England, on 25 Dec. 1642 (5 Jan. 1643 according to the Gregorian calendar). He showed, from a very young age, particular aptitudes for the study of natural phenomena, as well as for the construction of ingenious mechanisms and sundials, so his mother consented that he devote himself to the sciences and prepare for admission to the famous Trinity College at Cambridge. He entered there by competition in June 1661, and the well-known J. Barron, professor of mathematics, encouraged him in his studies for eight years and in 1669 obtained for him the appointment as "Lucasian Professor of Mathematics," ceding him the post. N., who had already before that time published several notable studies, among them the famous theorem for the expansion of the binomial for any exponent, was able to devote himself without other concerns to his preferred studies.

The twenty years between 1667, the year in which he obtained the degree of "Fellow" at Trinity College, and 1687, in which he published Philosophiae naturalis principia mathematica, was without doubt the period of N.'s most intense and fruitful work. He alternated theoretical studies and experiments in optics, which he set out in his lectures, with the fundamental studies on general mechanics and on the gravitation of bodies, and he attended at the same time to studies of mathematics and geometry; but little is known of their distribution over that period. Those who then lived with N. recall him as constantly absorbed in his meditations, often forgetful of food and sleep, averse to every pastime but always constant in practices of religion and charity. It is however known that in the early years of that period N. invented his reflecting telescope, which is still built today in enormous examples, and this earned him in Jan. 1672 the appointment as a fellow of the Royal Society of London, although he did not lack the usual criticisms of the envious. Of exceptional importance among others are two discoveries: the systematization of the foundations of mechanics and the discovery of the law of universal gravitation, set out at length in the Principia. Those discoveries, by their concurrence, placed N. forthwith among the greatest geniuses. Although reference is often made to a Newtonian dynamics, one must not forget that its general concept is due to the application of Galileo's experimental criterion. The first of his three laws, that of inertia, is certainly due to Leonardo da Vinci and Galileo; the second, that of the action of forces on material bodies, is fundamentally due to Galileo, who applied it extensively and recognized its great scope; by N. it was only formulated axiomatically in such a way as to make it serve for further systematic developments. Since, however, the application of forces (actions) to a given body necessarily implies the intervention of another body, for the complete consideration of the dynamic phenomenon it was also necessary to consider the effects that it underwent: hence the third axiomatic law, ordinarily called that of action and reaction, entirely due to N. On the basis of these three laws and a few definitions of fundamental concepts he succeeded in systematically constituting the dynamics that still today satisfies most of the requirements of physics.

The discovery of universal gravitation (v. GRAVITAZIONE), or rather of its law, since there was already an inkling of the generic notion, cost N. alternations of hopes and disappointments. The first and perhaps still somewhat vague investigations go back to 1665, and a legend would have them provoked by the chance fall of an apple from the tree, and by the thought that the force acting on the apple and compelling it to fall with uniformly accelerated motion toward the earth must be of a nature identical to that which held the moon in its orbit around the earth. They were taken up again fourteen years later and then again abandoned because, introducing into the calculations the value assigned to the diameter of the earth on the basis of Snellius's measurements, certain numerical divergences were found upon the definitive resumption of the same calculations. Finally in 1683, using for the diameter of the earth the more precise measurements of the meridian arc carried out by Picard, N. reached the hoped-for result, that is, the very well-known universal law that he set out in the third book of the Principia. In the following year the celebrated astronomer Halley, visiting N. at Cambridge, was informed of the situation and reported it to the Royal Society of London, which forthwith charged him to obtain the communication of the distinguished work, which was presented to it on 28 Apr. 1685. The authoritative association took under its patronage its publication, which took place in 1687. Subsequently, for over a century, the triumphs of celestial mechanics induced physics to consider as its ideal that of developing its theories in the sense of hypothetical action at a distance of the Newtonian type, not excluding the new electrical, magnetic and electromagnetic theories of the first half of the 19th century, forgetting that N. himself had openly manifested his repugnance to attributing to those actions any character of reality. Only the Faraday-Maxwell reaction later modified that tendency.

In the years immediately following, N., somewhat exhausted by the immense work, occupied himself chiefly with the perfecting and publication of his previous studies, almost all already set out in his lectures. From 1695, appointed inspector and then director of the Mint, he remained involved in the unpleasant controversies concerning his contributions to the creation of infinitesimal calculus in comparison with Leibniz. Surrounded by a consideration such as no other scientist had, in an eminent financial position, N. devoted his last years to biblical studies, the fruit of which were a commentary on the Apocalypse and a work on the prophet Daniel. He died on 31 March 1727 and was, with the greatest honors, entombed in Westminster Abbey.

Paolo Stranco