SIR ISAAC NEWTON

Evening Star, Issue 19559, 18 May 1927, Page 2

SIR ISAAC NEWTON

A GIANT IN INTELLECT [By Professor J. Aetude Thomson, in ‘John o’ London’s Weekly.’] With scientific piety ihe high-brow mathematicians, physicists, and astronomers commemorated on March 20 the death of Sir Isaacs Newton _2OO years ago. Although it seems to have been a miserable infant with little expectation of survival who was born of yeoman stock at Woolsthorpe, near Grantham, on Christmas Day, 1642, the year of Galileo’s death, it was a hearty veteran who attended a meeting of the Royal Society on February 28, 1727, and passed away peacefully in Kensington mi March 20 in the eighty-fith year of ids age. Of some great men who have done great things there may be doubt whether their capacity should he called talent or genius, but there has never been any hesitation in regard to Newton. ilis intellect reached a higher power than that of most other mathematicians, which is saying a great deal. He had in his own domain an intensity of insight, which lias never been surpassed, and ho saw things new. In his admirable 1 Makers of Science ’ Mr Ivor B. Hart recalls the story of a difficult problem which Leibnitz took six months to solve, while Newton cleared it up in twenty-four hours. He published the solution anonymously, but John Bernouilli, who had proposed the problem, at once recognised the masters hand, exclaiming: “Ex ungue leonera” (“even as the lion is Known by his paw”). Lagrange, who was himself one of tho most profound of mathematicians, was generous enough to that “ Newton was the greatest genius that ever existed.” The famous French astronomer Arago went the length of saying “ The efforts of the great philosopher were always superhuman; the questions which he did not solve were incapable of solution in his time.” Yet the one thing that everyone knows about Newton, apart from the falling apple and the dog Diamond, is the famous sentence: “I know not what the world may think of mv labors, but to myself it seems that I have been but as a child playing on the seashore; mow finding some prettier pebble or more beautiful shell than my lompanions, while the unbounded ocean of truth lay undiscovered before me.” This was over-modest, for he made the world new; but-it was a beautiful expression of the asymptotic quality of scientific advance, always getting nearer to, yet never reaching, completeness of description. Before sunrise on a summer morning one sometimes sees vague, disconnected objects standing out among the hills and dales, but when the dawn comes all are bound together in a luminous unity which seems over new. So it was that Newton’s revelation of order and unity gave mamkind a new world. “ Nature and Nature’s laws lay wrapped in night; God said: ‘Let Newton bcl’ and there was light.” In some ways this is the finest of all the eulogies, but we give two more. Leibnitz had a long and bitter controversy with Newton oyer the question of priority in discovering the calculus, but when the Queen of Prussia asked him what he thought of Newton he answered: “ Talcing mathematicians from tho beginning of tho world to the time when Newton lived, what he had done was much the better half.” Very striking

also is the sentence often quoted from Playfair’s Dissertation: “No one ever

left knowledge in a state so different from that in which he found it.” If we think of the inventions which followed from Newton’s ‘ Principia ’ we ! may perhaps say that he changed the | practical problem: of mankind more than any discoverer. In 1665 the University of Cambridge ! was closed owing to an outbreak of plague, and Newton retired to his honie at Woolstborpo and spent eighteen months in quiet meditation. _ It was then that ho linked tho falling apple to the falling moon. It matters not if wo reject the story of Newton’s attention being arrested by the apple falling in tho orchard—Mr Hart says it originated from Voltaire—tho point is that Newton showed that the same law of gravitation applies to all “falling” bodies. Ho calculated that the moon fell towards the earth 13ft in one minute. But according to the law that lie had thought out, that gravitation acted inversely as tho square of the dis- . stance, the moon should fall not 13fb, j but 15ft. “Ho therefore,” says Dr Bridges, “ quietly put the hypothesis aside; a striking example of scientific forbearance.” Seven years later Picard made a more exact measurement of the earth’s magnitude, and this correc- ■ tion in Newton’s data made fresh cali dilations possible, and the moon came into line. The theory of gravitation was gradually vindicated for the universe of gravitating; bodies, and though now subsumed by Einstein in a larger law, it remains within its immediate domain perhaps the most perfect of the laws of nature; that is to say, one of the most precise and adequate of for-

mulations. Having discovered about 1606 the mathematical method known as “ Fluxions,” corresponding to the Differential Calculus of to-day, Newton worked out the groat treatise known as the “Primcipia—the Mathematical Principles of Natural Philosophy,” in which, however, ho employed geometrical methods for his demonstrations. This work remains one of the half-dozen greatest achievements of man’s scientific genius. As Dr Bridges says in ‘ Tho New Calendar of Great Men ’: “ ‘ Tho Principia,’ notwithstanding the archaic form in which Newton thought fit to transpose his discoveries, will by ' many bo looked upon as tho greatest, I by ail as one of the two or three great masterpieces, of scientific intellect. In unity of purpose, though not in native i power, it surpasses tho work of Archi- ; modes; in tho importance of its application, though not in philosophic breadth, the ‘ Mecaniquo ’ of Lagrange.” I Keats said that ho could not forgive 1 Newton for having dissolved the won- ; der of the rainbow, but he would have ' been wiser if he had recognised, with Wordsworth, that in place of the minor wonder of the rainbow Newton gave i mankind a major wonder to contcm--1 plate—the nature of light itself. After ] all. it should not affect our appreciation of the rainbow much to know that I it is a natural analysis of white light | into component colors of different refrangibility, comparable to that which I Newton effected experimentally with ; his prism, but Newton’s greater achieve--1 mont was making the light itself more I intellectually luminous. It is very imi teresting to notice that while Newton’s . corpuscular theory of light—the cmis--1 sion of minute particles moving with great velocity in direct lines—has been For many years superseded by the utidulatory theory, which mterprets the phenomena as duo to electro-magnetic radiations propagated in the ether or in space, there has been a recent attempt on the part of Sir J. J. Thomson, tho leading authority on these questions, to bring the two theories together under a new interpretation. For it is thus that science advances, from thesis and antithesis to a new synthesis. Newton believed in absolute time and absolute space, but according to Einstein’s theory time and space are not independent, but interdependent. If this view prevails, and it seems to be prevailing, then the Newtonian system of dynamics must be radically revised. Einstein’s law of gravitation not only formulates all that Newton’s did, but it fits other facts which Newton’s theory could not, such ns tho distortion of the oval orbits of planets round the sun (confirmed by modern measurements for Mercury), and the deflection of light rays in a gravitational field such ns the sun supplies icon firmed by the British Eclipse Expedition of 1919). Tho average of two independent meas-

urcraonts of the deflection of a star s light in passing near the sun was l.b (seconds of angular distance), and Jtinstein’s theoretical prediction was 1.75! Einstein has come into direct conflict with Newton’s ideas of time and space and with Newton’s law of gravitation, but it would be misleading to say that Einstein lias superseded Newton. It is rather than Einstein’s. theory includes or subsumes Newton s and applies where Newton’s falls short, as in reference to orbits where the gravitational pull is much greater than the earth’s and in cases where the velocities dealt with are approaching.the velocity of light. There seems little doubt that Einstein’s theory has a larger applicability than Newton’s, hut perhaps it is too soon to say that it is the simplest and most consistent theory that can be arrived at.

For practical purposes it matters little, since m all ordinary cases Newton’s law of gravitation works well, and onr conceptions of time and space are of the nature of intellectual luxuries. As Professor E W. Hobson says in his ‘ Domain of Natural Science’; “When it is said that Einstein’s theory of gravitation has overthrown and superseded Newton’s theory that is in any case only true in a very limited sense. In ail ordinary astronomical cases Einstein’s theory gives the same results as Newton’s; it is only in very special cases that the differences between the results they lead to is sufficiently large to bo discernible by the means of measurement at our disposal.” So we can join whole-heartedly in doing honor to the memory of Einstein’s great precursor . who died 200 years ago.