IV.—Life of Sir Isaac Newton. THE name of Sir Isaac Newton has by general consent been placed at the head of those great men who have been the ornaments of their species. However imposing be the attributes with which time has invested the sages and the heroes of antiquity, the brightness of their fame has been eclipsed by the splendour of his reputation; and neither the partiality of rival nations, nor the vanity of a presumptuous age, has ventured to dispute the ascendancy of his genius. Sir Isaac Newton was born at Woolsthorpe, near Grantham, in Lincolnshire, on the 25th of December 1642. His father died a few months previous to this event. Newton was thus left to the care of a widowed mother. At twelve years of age he was sent to the public school at Grantham, where he seems to have been very inattentive to his studies, and very low in his class; but having received some ill-treatment from the boy who was above him, he laboured incessantly till he became his superior in the class, and from that time he continued to rise until he was the head boy. From the habits of application thus formed, the peculiar character of his mind was speedily displayed. During the hours of play, when the other boys were occupied with their amusements, his mind was engrossed with mechanical contrivances. For this purpose he provided himself with little saws, hatchets, hammers, and all sorts of tools; and among other picces of mechanism he constructed a wind mill, a water clock, and a carriage put in motion by the person who sat in it. When he attained his fifteenth year, he was taken home to assist in the superintendence of his small paternal estate, but instead of attending to the affairs of the farm, Newton was frequently found reading under a hedge; and the perusal of a book, or the superintendence of a water wheel of his own construction, too often absorbed all his thoughts, when the sheep were going astray, and the cattle were devouring or treading down the corn. His mother seeing his passion for study, and his dislike for every other occupation, sent him back for a few months to Grantham school, and on the 5th of June 1660, he was admitted into Trinity College, Cambridge. The penetrating mind of Newton regarded the elements of Euclid as self-evident truths, and without any preliminary study, by his genius and patient application alone, he made himself master of Descartes' Geometry and other algebraic writers. In 1668 he took his degree of Master of Arts, and in 1669 he was chosen to fill the mathemati cal chair in the room of Dr Barrow, the celebrated theologian and mathematician. The first of his grand discoveries seems to have been that of the different refrangibility of the rays of light, which he established in 1666. Though the exhibition of colours by the prism had been often made previous to the time of Newton, yet no philosopher seems to have attempted to analyse the phenomena. Taking a triangular glass prism, and having made a hole in one of his window. shutters, and darkened his chamber, he let in the light, which passing through the prism, was so refracted as to exhibit all the different primary colours, viz. red, orange, yellow, green, blue, indigo, and violet, on the opposite wall. After a variety of experiments with the prism, he drew the grand conclusion, that light was not homogeneous, but consisted of rays, some of which were more refrangible than others. His" Optics" appeared in English in 1704, and a Latin edition in 1706; these editions have frequently been reprinted, both in England and on the Continent, and there perhaps never was a work of profound science so widely circulated. In the year 1666, when the plague had driven Newton from Cambridge, he was sitting alone in the garden at Woolsthorpe, and reflecting on the nature of gravity, that remarkable power which causes all bodies to descend towards the centre of the earth. As this power is not found to suffer any sensible diminution at the greatest distance from the earth's centre to which we can reach, being as powerful at the tops of the highest mountains as at the bottom of the deepest mines, he conceived it highly probable that it must extend much farther than was usually supposed; that the moon might be retained in her orbit by the force of gravity, and if so, that the primary planets must also be carried round the sun by the same power. In attempting to verify this by calculation, he adopted the common estimate of the earth's diameter then in use, and supposed that each degree of latitude contained sixty English miles. Owing to this error the result did not correspond with actual observation, which threw a doubt upon all his speculations, and he therefore, at that time, discontinued all farther inquiries into the subject. An accident, however, of a very interesting nature induced him to resume his former inquiries, and enabled him to bring them to a close. In June 1682, when he was attending a meeting of the Royal Society of London, the measurement of a degree of the meridian, executed by M. Picard in 1679, became the subject of conversation. Newton took a memorandum of the result obtained by the French astronomer, and having deduced from it the diameter of the earth, be immediately resumed his calculation of 1666, and began to repeat it with these new data. In the progress of the calculation he saw that the result which he had formerly expected was likely to be produced, and he was thrown into such a state of nervous irritability that he was unable to carry on the calculation. In this state of mind he intrusted it to one of his friends, and he had the high satisfaction of finding his former views amply realized. The influence of such a result upon such a mind was of the most exciting character. The whole material universe was spread out before him; the sun with all his attending planets;-the planets with all their satellites ;the comets whirling in every direction in their eccentric orbits; and the systems of the fixed stars stretching to the remotest limits of space. All the varied and complicated movements of the heavens, in short, must have been at once presented to his mind, as the necessary results of that law which he had established in reference to the earth and the moon. Newton followed up this discovery by demonstrating that the tides of the ocean depend upon the joint attraction of the sun and moon, principally that of the latter;a discovery resting upon the same theory of universal gravitation. His great work, the Principia, embracing these and other investigations, was published in 1687. To enumerate and explain his labours in mathematical investigations would far exceed our limits. His superior excellence indeed excited the envy of many of his con temporaries, but his penetrating genius, seconded by his moral excellence, baffled all attempts to depreciate his fame. Bernouilli, a Swiss philosopher, transmitted to the most distinguished mathematicians in Europe two problems for solution. Leibnitz, one of these distinguished men, was so struck with their beauty, that he requested Bernouilli to extend the time granted for their solution from six months to twelve. Newton sent a solution of them both to the President of the Royal Society on the day after he received them. Leibnitz, in 1716, prepared another, "for the purpose," as he expressed it, "of feeling the pulse of the English analysts." It was received by Newton about five o'clock in the afternoon, as he was returning from the mint, and though the problem was extremely difficult, and he himself much fatigued with business, yet he finished the solution of it before he went to bed. In an account, however brief, of the labours of the illustrious Newton, it would be unpardonable to omit all allusion to his theological studies. That he, who among all the individuals of his species possessed the highest intellectual powers, was not only a learned and profound divine, but a firm believer in the great doctrines of religion, is one of the proudest triumphs of the Christian faith. Cherishing its doctrines, and leaning on its promises, he felt it his duty, as well as his pleasure, to apply to it that intellectual strength by which he had successfully surmounted the difficulties of the material universe. Thus uniting philosophy with religion, he dissolved the league which genius had formed with scepticism, and added to the cloud of witnesses the brightest name of ancient or of modern times. The life of Newton was not passed unmarked by honours and rewards. In 1699 he was appointed master of the mint, a situation in which his mathematical and chemical knowledge was of great service to the nation. In 1687 he was chosen one of the nine delegates, who were appointed to defend the independence of the university of Cambridge, against the unconstitutional encroachments of James II.; and in 1688 he was elected to represent that learned body in Parliament, and again in 1701. He was chosen President of the Royal Society of London in 1703, an office to which he was annually re-elected during the remaining twenty five years of his life; and in 1705 the honour of knighthood was conferred upon him by Queen Anne. The social character of Sir Isaac Newton was such as might have been expected from his intellectual attainments. He was modest, candid, and affable, and without any of the eccentricities of genius, suiting himself to every company, and speaking of himself and others in such a manner that he was never even suspected of vanity. His generosity and charity had no bounds, and he used to remark, that they who gave away nothing till they died, never gave at all. His wonderful faculties continued unimpaired even in age, and his temperate habits and cheerful disposition long preserved a constitution naturally sound from the usual infirmities of life. A few years previous to his death, however, he suffered from severe affliction, and the paroxysms of the disorder were sometimes so violent that large drops of sweat followed each other down his face. Under these afflicting circumstances, the philosopher and the Christian were equally conspicuous. He never uttered a cry or a complaint; but during the intervals of relief which occurred, he smiled and conversed with his usual gaiety and cheerfulness. Nature being at last worn out, he resigned his breath on the 20th of March 1727, in the eighty-fifth year of his age. He was honoured with a splendid funeral, and a monument in Westminister Abbey, with a Latin inscription, of which, as it portrays his character and discoveries with elegance and nervous precision, we here subjoin a literal translation: Here Lies SIE ISAAC NEWTON, Knight, The motions and figures of the Planets, The different refrangibilities of the Rays of Light, That there has existed such and so great AN ORNAMENT OF HUMAN NATURE. Born 25th December, 1642, Died 20th March, 1727. SIR D. BREWSTER, abridged. |