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We have seen that as Galileo was called off this world's stage, Sir Isaac Newton was ushered on, the death of the former occurring in the same year as the birth of the latter, which was in 1642.
Judging by appearances the infant Newton seemed to have but a poor chance in this world; he was so very small and so delicate. Indeed, he had such a slender hold on life that two women, who were sent to a neighbouring house for some medicine for the infant, did not expect to find him alive on their return. Newton used to tell how he had often heard his mother say that when he was born he was so small that they might have put him into a quart mug. His father had died a few months after marriage, at the age of thirty-six, so that our hero was born an orphan. The widowed mother named the infant Isaac after his deceased father.
The manor-house of Woolsthorpe (Lincolnshire), in which Newton was born, had been in the possession of the family more than a hundred years. It produced only a small income, about thirty pounds per annum, leaving out of account what could be made by working the farm.
When Isaac was still a child his mother was married to the Rev. Barnabas Smith, rector of a neighbouring parish. Isaac was left under the care of his maternal grandmother, who saw that he got as good an education as could be got in the neighbouring villages. At the age of twelve he was sent a little farther afield, to Grantham. Although this town was only half a dozen miles distant, it was necessary for the boy to board in the town, so that he might attend the Grammar School. He boarded with an apothecary named Mr. Clark.
Isaac had not distinguished himself at school, unless by being very often in the lowest place in his class, but from what follows we shall see that he cannot have been taking any very serious interest in his lessons; probably his mind was engrossed in other thoughts. But one day, as he was on his road to school, a schoolmate gave him a very nasty kick in the stomach, whereupon Newton challenged the boy to fight. The duel came off in the churchyard, and Newton proved the victor, but not content with this physical victory, he determined to get above this boy in his class. By applying his mind to his lessons, Isaac not only surpassed his antagonist, but soon found himself at the top of the school.
Had Newton lived at the present time he would, I fear, have been unpopular, for he did not join much in his schoolfellows' games, although he found plenty of time to construct models of machines and other contrivances. He made an excellent working model of a large windmill that was being erected in the neighbourhood of his school. Among the other things that he made there was a water-clock. The idea was, of course, a very old one; he allowed water to drop at a regular rate, and as the level of the water in the cistern fell, a wooden float operated the hand of the clock. Rough and ready as all such "clepsydras" were so far as keeping good time, the inmates of the apothecary's house often peeped into Isaac's bedroom to see what time it was. Hour-glasses, or as they are more descriptively named sand-glasses, were the most common time-keepers in those days.
As Newton had a definite hobby he would never find time to hang upon his hands. He was keen in everything at which he worked, being described as "a sober, silent, and thinking lad." It is refreshing to see a glimpse of innocent mischief in this seriously-minded boy. He had shown his playfellows how to construct paper kites, and in what manner they would fly best. He had also constructed paper lanterns to hold candles and light the boys to school on dark winter mornings. This led to the one little piece of mischief recorded of his boyhood. Knowing that the country folk were very suspicious about comets, Newton tied one, of his lanterns to the tail of a kite, and put this up in the air on a dark winter night; he succeeded in terrifying the villagers.
One occasionally sees, in the windows of bird-fanciers, small mouse-mills in which a live mouse gives motion by running in a sort of treadmill. It is interesting to note that this was invented by Isaac Newton in his boyhood. According to one learned French writer, Newton called his mouse the Miller, "because it directed the mill, and ate up the flour as a real Miller might do."
When Newton was fourteen years of age his step-father died, and his mother returned to the manor-house. As Isaac had now reached the age at which most boys were ready for work, his mother thought it was time he should begin his apprenticeship to farming, and so he returned home from Grantham.
Although Isaac's twice-widowed mother was now Mrs. Smith, I shall continue to speak of her as Mrs. Newton. She had the small income derived from Woolsthorpe, and a larger income (about eighty pounds per annum) from a neighbouring estate which she possessed, but it was necessary to increase the annual income by farming the land around the manor-house. At the same time, we must remember that money went much farther in those days.
As Isaac would be the proprietor of Woolsthorpe it was natural to take for granted that he was to be a farmer. With this object in view he was sent to Grantham on each market day, under the care of an old and trusted man-servant. But Isaac made a shockingly bad apprentice. As soon as they reached Grantham, and had put up their horses at the Saracen's Head Inn, Isaac left the old servant to look after the marketing, while he himself went off to his old lodging in the Apothecary's house, to spend his time among the chemist's stock of books, and remaining there until called for on the return journey. The young master's conduct must have been very disappointing to the old servant. It would be hopeless to teach him anything about marketing; indeed, sometimes the old man did not succeed in getting his pupil to reach Grantham. On these occasions the would-be instructor had to be content to leave the boy under a hedge by the roadside with some book of study, and on the return from the Grantham market he would find Isaac still buried in his book.
I have no doubt that this trusted old servant would feel compelled to inform Mrs. Newton that Isaac would never make a farmer. Indeed, she must have foreseen this herself, for when she sent Isaac to the fields to watch the sheep or cattle, he would perch himself under a tree, intent on some book, or keenly interested in making some model, quite oblivious of the fact that his charges were wandering among the corn. Some parents would have taken the books out of the boy's reach, and insisted that he must attend to his duties, but Mrs. Newton acted more wisely; the boy was not reading for amusement, he was thirsting for knowledge. We may presume that she consulted her brother who was rector of a neighbouring parish, for it seems to have been the boy's uncle who suggested that the idea of farming should be abandoned, and that Isaac should return to Grantham to be prepared for college.
Isaac still found time for working with his hands. Having made close observations of the shadows produced by the Sun on the front of the apothecary's house, he set about constructing a sundial. It was quite an ordinary thing for the country people to consult "Isaac's dial "when they wished to know the time. Of course, sundials are of very ancient origin, but dials had to be made to suit the place and situation. Isaac had no knowledge of how to adjust these to the latitude of a place, and so he depended entirely upon his own observation. He erected two similar dials on the manor-house at Woolsthorpe, and one of the stones of the wall upon which the dial was carved is now preserved in London by the Royal Society, not because of any scientific novelty, but because of its sentimental value.
Newton used to tell, in later life, how he remembered the great storm that occurred on the day on which Oliver Cromwell died? The force of the wind was very great, and Newton had attempted to measure it in a rather ingenious manner. First he jumped with the wind, marking off the longest distance he could cover. Then he jumped against the wind, making a similar measurement, and afterwards comparing the difference between these longest jumps. When his companions were surprised at his saying that any particular wind was a foot stronger than any wind he had measured before, he would take them to see the marks of his jumps. Of course, there was a very large personal equation entering into any such measurement.
At the age of eighteen years Isaac was sent to Trinity College, Cambridge, at which college his uncle had been a student. It may be noted in passing that Cambridge had not been long inclined to Mathematics; it was only in the beginning of the seventeenth century that the University authorities showed themselves specially interested in Mathematics.
Newton did not take any distinguished place in his college classes. His schooling had been inferior to that of the majority of his fellow-students. But Newton had made a name for himself in the small world which he had left at Grantham. We are told that on the day on which Newton left the public school, in order to go to Cambridge, the old schoolmaster, with the pride of a father, placed his favourite pupil in the most conspicuous place in the school, and, with tears in his eyes, having made a speech in praise of Newton's character and talents, held him up to the school as a proper object of their love and imitation.
We know practically nothing of Newton's first few years at Cambridge, but two recorded facts show how very easily he mastered a new subject. His clergyman uncle had given him a book on Logic while he was at home, and so thoroughly had Newton mastered this subject that when he attended the lectures on Logic at college, his teacher was surprised to find the lad was further advanced than he himself was. This teacher invited Newton to attend a series of lectures he proposed giving to some Gentlemen Commoners. And in order that the youth might be able to follow the lectures his teacher advised him to read Kepler's Optics. Here we have a very direct link with our hero of Chapter VII, who had died only twelve years before Newton's birth. Newton mastered Kepler's book so thoroughly that when the lecture time came his teacher found the student was conversant already with all that he could tell him.
About three years after Newton's arrival at Cambridge, he happened to be at a fair which was held on the outskirts of the town. There he bought a book on Astrology, in which he came upon a geometric figure which he could not understand. In order to find out the meaning of this figure he bought a book of Euclid, and after glancing through it until he found what he required, he cast it aside, surprised that any one should trouble to demonstrate so many truths that were so self-evident. Some readers may be a little surprised at Newton's verdict, for in our schooldays a number of the problems did not seem to us so very Q.E.D., which symbols, although signifying quod erat demonstrandum, we pretended to read "quite easily done." Indeed, we sometimes used this translation in a rather sarcastic sense. But Newton himself found out later that the problems were not all so very self-evident as to require no explanation, for when he was examined for a scholarship, the Professor of Mathematics (Dr. Barrow) formed a very poor opinion of Newton's knowledge of Euclid. And at a later period in life Newton writes: "I regretted having applied myself to the works of Descartes (Geometry), and other algebraic writers, before I had considered the 'Elements of Euclid' with that attention which so excellent a writer deserved."
When twenty-two years of age Newton took his B.A. degree, but evidently without taking any prominent place in the examination list. In this same year (1665) the college was dismissed because of the Great Plague, which in the autumn cut off sixty thousand people in London alone. It was during this vacation at his own home that Newton saw the historic apple fall from the tree.
I remember, when I was a boy, listening to a lecture on Newton. The lecturer was an amateur, and he sent us away with the idea that it was Newton who discovered gravitation or, in other words, that it was he who first suggested that apples fell down because the Earth attracted them and all other bodies to it. I wonder how the other members of the audience felt when they found later that gravitation was well known long before Newton's time, and that his discovery was of far greater interest because he extended the idea of gravitation far beyond the compass of this Earth. He suggested that it was the same attractive force which bound the Moon to the Earth, and the Earth and the other planets to the Sun.
The story of the falling apple has been disbelieved by some writers, because Newton did not mention it to the scientists to whom he stated his first ideas of Gravitation. Newton himself did not record the story, but that is not very convincing evidence, for he might not consider such an apparently trivial affair to be of general interest. But the story was confirmed by Newton's niece, who lived in his household for the last twenty years of his life. She told Voltaire that the story was true, so that our only questioning of this evidence could be whether the niece ever got the story confirmed by her uncle, or whether she herself believed the story because she had probably heard it so often. Sir David Brewster saw the apple tree in 1814, and took away part of its roots, but in 1820 the tree was so decayed that it was cut down, the wood being carefully preserved thereafter.
The truth seems to be that Newton, then about twenty-three years of age, was sitting under the apple tree, thinking about the forces of Nature. He was well acquainted with Descartes' ideas of the planets being carried round in whirlpools of a space-pervading fluid, each having its own eddy by which it was impelled and kept in position. Probably this theory, though long upheld, would appear too fanciful to Newton, because he had calculated by means of Kepler's Laws (mentioned in Chapter VII) that a central force at the Sun would account for the motion of the planets at their respective distances. The falling apple would suggest to him the idea that the common force of gravitation might extend beyond this Earth, and so he sought to apply its laws to the whole Universe. But when he calculated what the pull of Gravity would be at the distance of the Moon, he did not get his figures to agree with observed facts regarding the velocity of the Moon, and so the great philosopher laid the matter aside. Indeed, he seems to have been quite satisfied that his idea was a mistaken one, for he, tells us later that he gave no further thought to the matter, nor did he even mention his idea to any one.
After Newton had remained at his country home for about two years, the Plague had so far abated that he returned to Cambridge. He would have little time for any original research work till he passed his final examination for his MA. degree. In this examination he came out twenty-third on the list. It is difficult for us to realize that such a great genius as Newton should not have been an easy first in all examinations. Indeed, one is inclined to surmise that the great thinker did not give his undivided attention to the subjects for the examinations; he would be more concerned in acquiring knowledge that might be more useful to him, than what was of temporary interest to enable him to pass an examination. It is evident that for some years his studies covered a very wide field.
Dr. Barrow, the Professor of Mathematics, was so impressed with Newton's mathematical powers, that he decided to secure Newton's election to the Chair, while he himself resigned and devoted his energies to the study of Theology. Newton, in this way, became professor at, the age of twenty-six.
The name of Newton is very prominent in connection with the subject of Light, and it is evident that he had mastered a great deal of that subject before he became Professor of Mathematics. For while Dr. Barrow still occupied that important Chair, he had written a book on Optics, and he had asked Newton to read the manuscript for him. Young Newton had been able to make some important suggestions, but some parts of the subject were still primitive. A single quotation from Dr. Barrow's book will show the ideas of colour which he and Newton entertained at that time. "The blue colour of the sea arises from the whiteness of the salt which it contains, mixed with the blackness of the pure water in which the salt is dissolved."
It was the duty of the Professor of Mathematics in these days to lecture once a week on such subjects as Astronomy, Geography, or Optics, and Newton took Optics as the subject of his early lectures. These lectures contained a great deal of original research, but he did not publish them until after his election to the Royal Society of London, which was a few years later.
There is preserved an interesting letter written by Newton about this time, and as it throws some light upon his character, a few quotations will be of interest. A young gentleman, who was going abroad to see the world, had written to Newton asking advice. A few of the general rules laid down in Newton's reply are these: ". . . It is the designe of travellers to learne, not to teach. . . . If you bee affronted, it is better in a forraine country, to pass it by in silence, and with a jest. . . . Your credit's ne'er the worse when you return into England, or come into other company that have not heard of the quarrell. But, in the second case, you may beare the marks of the quarrell while you live, if you outlive it at all. . . . Such excuses as these—'He provok't mee so much I could not forbear'—may pass among friends, yet amongst strangers they are insignificant, and only argue a traveller's weaknesse."
Then in a long list of things to be observed by the traveller, we notice that Newton had some belief in Alchemy, for one instruction to the young man is: "I you meet with any transmutations out of their own species into another, as out of iron into copper, out of any metall into quicksilver, . . . those, above all, will be worth noting, being the most luciferous." And again he says: "There is in Holland one—Borry, who some years since was imprisoned by the Pope, to have extorted from him secrets (as I am told) of great worth, both as to medicine and profit, but he escaped into Holland where they granted him a guard. I think he usually goes clothed in green. Pray enquire what you can of him, and whether his ingenuity be any profit to the Dutch. You may enquire if the Dutch have any tricks to keep their ships from being all worm-eaten in their voyages to the Indies."
In laying down the general rules in this letter Newton remarks that his friend will no doubt have considered many of these already—"but if any of them be new to you, they may excuse the rest; if none at all, yet is my punishment more in writing than yours in reading."
The foregoing letter is sometimes referred to as having been written by Newton to "a young friend." It is true that the friend was young, but Newton was one year younger. I remark upon this because, if one reads this celebrated letter by itself, one is apt to picture Newton as a man of advanced years, whereas he was only twenty-six years of age at the time he wrote this letter.
We have some interesting information concerning Newton's life at college, written in the year in which Newton died. It was written in a letter by the son of John Wickens; the father had been Newton's chamber-fellow at college for about twenty years. The following extracts from this letter will be of interest: "My father's intimacy with him came by mere accident. My father's first chamber-fellow being very disagreeable to him, he retired one day into the walks, where he found Mr. Newton solitary and dejected. Upon entering into discourse, they found their cause of retirement the same, and thereupon decided to shake off their present disorderly companions and chum together, which they did as soon as conveniently they could, and so continued as long as my father stayed at College.
"I have heard my father often say that he has been a witness of what the world has so often heard of Sir Isaac's forgetfulness of food when intent upon his studies; and of his rising in a pleasant manner with the satisfaction of haling found out some proposition without any concern for a seeming want of his night's sleep, which he was sensible he had lost thereby.
"He was turning grey, I think at thirty, and when my father observed that to him as the effect of his deep attention of mind, he would jest with the experiments he made so often with quicksilver, as if from thence he took so soon that colour.
"We have been the dispensers of many dozens of Bibles sent by him for poor people, and I have now many by me sent from him for the same purpose, which as it shows the great regard he had for religion, I cannot but desire that by you it may be made public to the world."
Then we have some interesting records also written at the time of Newton's death by one of his assistants. This writer, Dr. Humphry Newton, evidently not a relative, was with Sir Isaac during the time he wrote his world-famous Principia, at which time Newton was about forty-five years of age. The following are a few extracts from this letter. "His carriage was very meek, sedate, and humble, never seemingly angry, his countenance mild, pleasant, and comely. I cannot say I ever saw him laugh but once, which was at that passage which Dr. Stukeley mentioned in his letter to your honour, which put me in mind of the Ephesian philosopher, who laughed only once in his lifetime, to see an ass eating thistles when plenty of grass was by." The occasion to which the writer refers was when Sir Isaac asked a friend, to whom he had lent Euclid, what progress he had made in that author, and how he liked him. He answered by desiring to know what use and benefit in life that study would be to him. Upon which Sir Isaac was merry.
The writer of the letter goes on to relate how Newton kept so very close to his studies that he took no exercise, thinking all hours lost if not spent in study. He had few visitors, but he took delight in their company when they spent an evening with him. "When invited to a treat, which was very seldom, he used to return it very handsomely, and with much satisfaction to himself." He was so very intent upon his studies that "oftimes he has forgot to eat at all, which when I have reminded him he would reply 'Have I?' and then making to the table, would eat a bit or two standing, for I cannot say I ever saw him sit at table by himself.
"He very rarely went to dine in the hall, except on some public days, and then if he has not been minded, would go very carelessly, with shoes down at heels, stockings untied, surplice on, and his head scarcely combed."
One is not surprised to learn that Newton was often very absent-minded; he was so absorbed in study. His assistant says: "At some seldom times when he designed to dine in the hall, he would turn to the left hand and go out into the street, then making a stop when he found he had made a mistake, would hastily turn back, and then sometimes instead of going to the hall, he would return to his chamber again. In his chamber he walked so very much that you might have thought him to be educated at Athens among the Aristotelian sect. . . . I believe he grudged the short time he spent in eating and sleeping. . . . He was very charitable, few went empty-handed from him."
Dr. Stukeley, who was a personal friend of Newton, although forty-five years younger than our hero, has left us many anecdotes concerning Newton. From one jotting in the doctor's diary it is evident that Sir Isaac could not have been a musical enthusiast. The doctor happened to remark that he had just been to an opera, whereupon Newton said that he had never been at more than one; "the first act he heard with pleasure, the second stretch'd his patience, at the third he ran away."
Then the learned doctor gives us some illustrations of Newton's absent-mindedness. When he had friends to entertain, if he went into his study to fetch a bottle of wine, there was danger of him setting to work and forgetting all about the waiting friends.
On one occasion when he was riding home he led his horse up a hill, and when he desired to remount, he found that his horse had slipped the bridle and gone away without his perceiving it, and he held only the bridle in his hand all the while.
We have seen from the letter of Sir Isaac's assistant that the Philosopher was very careless about his dress and personal appearance. It was quite natural that a man whose mind was so absorbed in study, and who even grudged time spent in eating, should find little time to get his hair cut regularly, or to spend time in looking after his clothing; there was no affectation in Newton. Dr. Stukeley confirms Newton's carelessness of dress: "He would go out, and would have walked the length of a street before he noticed he was not dressed, and therefore had to hasten back to his home quite ashamed."
On one occasion Dr. Stukeley called to see Newton, who happened to be, as usual, absorbed in some problem in his study. The visitor waited, possibly thinking that Sir Isaac would not be long, as his dinner was already served on the table. After waiting a very long time the learned doctor, becoming both impatient and hungry, sat down at, the table and ate the chicken prepared for Sir Isaac. After a further spell of waiting the great Philosopher put in an appearance, and having greeted his friend he sat down at the dinner-table. On finding nothing but bones he merely remarked that he had quite forgotten that he had already dined. It was too bad of the younger man playing this trick upon Sir Isaac; no doubt he quieted his conscience by the knowledge that his old friend was very guilty of neglecting his food.