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Newton: the Man 39-48

Dissection of the Eye

Newton, was evidently, not a gardener, since there were no books on botany or gardening in his library. From his knowledge of the structure of the eye, it seems highly probable - almost certain - that he had done a little dissection of this organ: but this is only conjecture, there appears to be no direct evidence. I base my judgment - and say ``almost certain'' - on ``a manuscript in his own handwriting, which we found among the family papers, containing some accurate observations and experiments on the form and dimensions of the eye of a sheep, and accompanied with an outline drawing on a large scale of a section of the eye'' (Brewster).

Personal Research

When Newton says, ``The dimensions of this figure, taken from a sheep's eye, are as followeth: By Experiment,'' this to my mind, is almost certain evidence that Newton made the measurements himself; he would not have been so emphatic on second-hand evidence.

Mechanical Talent

As to Newton's gifts as a mechanic - an artisan, say - we have seen that he was a very first-rate grinder and polisher of glass, though none of the lenses he made are extant. The Royal Society possesses lenses made by Huyghens, but none made by Newton.

The Reflecting Telescope

A sample of his work, as a metal worker, is to be seen in the Royal Society's Library in the form of the reflecting telescope he made and presented to the Society. The work is distinctly good, although it was not made for show, but simply for his private use. It is said to have been made about 1671.

Amateur Carpentry

We have heard a great deal about his work as a carpenter, when he was a boy, but we have no authentic work of his to judge from. There is, however, in the Royal Society's Library a chair known as ``Newton's Chair.'' If this is genuine - and there appears to be no reason to question it - I fancy that this chair is probably more than ordinarily interesting, since I suggest it was the work of Newton's own hands.!If it is examined carefully it will he evident that it was made hy an amateur and not by a professional chair-builder. The joinery is distinctly good, and quite up to the work of a professional, but the design is rather faulty, especiaUy the method of attaching the arms. These were so weak that special bars of metal have been added later in order to strengthen them. Whether this was done by Newton, or was added later, it appears impossible to say.

This concludes all that I can find bearing on Newton's character and aptitudes. In person we are told that Newton was inclined to be short and, from his portraits, one would say stockily built.

There are many portraits of Newton. Probably the most pleasing one is the half length painted by Kneller; which is also perhaps the best known, from the engravings made from it. I do not think, however, that this is a good likeness, since the face is very long and refined looking, whereas we know from the mask, which is in the Royal Society's Newtoniana that Newton's face was square and massive. Kneller, we know, was notorious for lengthening the faces of his sitters.

The Best Likenesses

As likenesses, the two best portraits of Newton are, in my opinion, the oil painting which he himself presented to the Royal Society, and which now faces anyone going up the staircase. The face corresponds well with the mask, and doubtless Newton himself thought it a good portrait - though, as I have suggested previously, he was not perhaps a good judge of a work of art. The other is the small bust in ivory, now in the British Museum, by Le Marchand, and which, as I have said, appears to he little known. In support of this statement I may point out that I first saw a pencil drawing of this bust at the Royal Society, and being desirous of knowing where the original was, I was told on inquiry at the Royal Academy that nothing was known of Le Marchand - his name even being unknown, though ``Marchant,'' a gem-engraver, and of a later date, was quoted. Eventually I was able to trace this little bust to the British Museum.

It is a very fine piece of work, and shows much more ``character'' than the Royal Society's oil painting. Since Dr. Mead, who was a great collector and judge of artistic objects, was almost certainly responsible for the production of this bust, we may feel sure tt1at he considered it a good portrait. The artist, also, in signing it ``De Vivo,'' must have been specially pleased with it. The frontispiece which is a photographic reproduction, will speak for itself.

The Apple Story

I will conclude this sketch with a short discussion on what may be called the ``Apple Story,'' or, better, the ``Apple Moon'' Story: a story round which a great deal of improbable fiction has been written. Let me recapitulate it.

Reconstructing the Scene

We know that Newton's college was ``dismissed'' on the 8th August, 1665 on account of the Plague, and Newton is said to have left a short time before. The weather, we also know, was very hot and oppressive, so that we may imagine that he went out in the cool of the evenings to sit in his orchard, which faces the house, on the west side, but is on much higher ground. It is natural, further, to suppose that he sat facing the house, i.e. facing the east. The year having been very hot and dry, the apple trees would have had many unripe and dry apples on them, which would fall occasionally. Let us imagine that on one evening, near the full moon, Newton is sitting, as described, in his orchard. Since he had written a paper on his ``Fluxions'' in a waste book on May 20th, 1665, as well as a third one dated May 16th, 1666, it is not unreasonable to suppose that he was thinking of his ``Fluxions,'' and we may also suppose that he had closed his eyes. An apple falls, and (in the intense quiet of a country evening) causes him to open his eyes, when he sees the glorious sight of the harvest moon, facing him. These two occurrences can easily be supposed to have started a new train of thought, which I may sum up as:

A Rough Calculation

If the law of gravitation was the inverse square of the distance, it would be easy to check this by the rate of the fall of the moon towards the earth. He makes the necessary and not very difficult calculation and finds the result is fairly accurate; or, as he himself recorded it, ``found them answer pretty nearly.''

Earlier Works

Now the story, as it is generally related, says: 1. That this was the occasion when ``Newton's mind was first directed to the subject of Gravity'' (Brewster's Memoirs). Why Brewster should have said this, is difficult to understand, since his book is filled with facts which make it appear incredible; many people had thought of gravity before Newton - Brewster gives a long list of them, and he says specially (after referring to Kepler's work), ``Our Countryman, Dr. Gilbert, in his celebrated book De Magnete, published in 1600, had about the same time announced similar opinions on Gravitation. He compares the Earth's action upon the Moon to that of a great loadstone; and in his posthumous work which appeared half a century afterwards, he maintains that the Earth and the Moon act upon each other like two magnets, the influence of the Earth being the greater on account of its superior mass. But though these opinions were a step in celestial physics, yet the identity of the Gravity which is exhibited on the Earth's surface by falling bodies, with that which guided the plants in their orbits was not revealed either to the English or the German philosopher'' (Brewster) [Italics added.]

Law of Inverse Squares

Not only had astronomical gravitation been thought of by many philosophers before Newton, but the ``Inverse Square Law'' had also been suggested. We find that, in 1645, ``After refuting the magnetic notions of Kepler, Bouilland maintained¹ that the force of attraction must vary reciprocally as the square, and not, as Kepler asserted, in the simple ratio of distance'' (Brewster). [Italics added.]

Is it imaginable that Newton was not aware of all this, since we are told that he had done a good deal of astronomical work in I664? I absolutely refuse to believe it.

What Newton Did

What Newton did on this occasion was to realise that the truth of the law, and its universality, could be tested by reference to the moon. There were several men at that time who might have thought of this and were fully as competent as Newton to make the necessary calculations, if they had thought of it. They did not: Newton did. Voila tout!

Measuring the Earth

It is also related that Newton - ``being away from his books,'' etc. - did not know the correct size of the earth, and therefore the true distance of the moon, and he therefore found that his calculalions gave incorrect results, i.e. results which did not agree with the theory. Some writers go so far as to say that the correct measure of the earth was not then known. But Norwood, in 1636, measured the distance from York to London; he then assumed that the earth was a perfect sphere, and says: ``These reduced into English miles . . . shew the diameter of the Earth to be 7,966 miles and somewhat more, and the semi-diameter 3,983'' (Sealnan's Practice, 5th Edition, 1662).

This little hook we see was in its fifth edition in 1662. Is it conceivable that Newton did not know it?

Newton's Reasoning

If it is not presumptuous I would suggest that Newton's reasoning was somewhat as follows:
Since the moon is 60 radii of the earth distant, if the law of gravitation is the ``inverse square law,'' it would follow that if an apple falls 16 feet in one second on the earth, the moon ought also to fall towards the earth, 16 feet in one minute. Assuming, in round numbers, the radius of the earth to be 4,000 miles, and the time of a complete revolution of the moon to be 27¼ days, then:

The Calculation

Putting D = circumferential distance travelled by the moon in one minute,
E = distance fallen by moon in one minute,
and R = radius of moon's trajectory (assumed as a circle),
then by Euclid Book III, Proposition 36: E(E x 2R) = (tang)² = E² × D².

Calculated out, we get (if my arithmetic is correct) E=15.95 feet, which Newton considered a good approximation; it was ``pretty nearly'' in agreement.

Problem of Publication

It has frequently been asked, Why did not Newton publish this result? One might, in the old Hebrew fashion, answer this question by asking another: Why did not Newton publish his three small papers on ``Fluxions''? Even he considered them important enough to enter in his Waste Book, but he did not, apparently, consider this ``moon calculation'' of sufficient importance. In modern slang, we must be satisfied with the explanation that Newton ``was not built that way.'' He hated advertising himself. We read that somewhere about this time Dr. Barrow wished to submit a paper of Newton's to the Royal Society, but Newton stipulated that his name was not to be mentioned.

Mass of the Earth

Besides this, we must remember that Newton did not at that time know what was the true ``distance'' to be taken. It was only a good many years later that he was able to prove that the action of gravity was as if the mass of the earth was concentrated at its centre of gravity. He had assumed this in his calculation, but it was nothing better than an assumption at that date.

Reasonable Assumption

It was certainly reasonable enough to suppose that the ``centre of the earth'' was sufficiently accurate if the distance was as great as that between the sun and the earth; but was it accurate enough for the comparatively short distance of the moon, or the still shorter distance of the apple?

A Forgotten Reference

We find in Brewster's (Vol. II, p. 416, note) a reference to a memorandum by Conduitt, which reads:

``In the same year (at his Mother's in Lincolnshire) when musing in a garden, it came into his thoughts that the same power of Gravity which made an apple fall from the tree to the ground was not limited to a certain distance.''

This note appears to have escaped general observation. It quite agrees with my ``reconstruction'' of the occurrence, as given above.

I have entered into this question at some considerable length because an American author (Prof. Florian Cajori) has lately devoted a long chapter to it, but leaves the question of Newton's non-publication as rather a mystery. I quite agree with his concluding remarks, however, that the delay was not due to error in the size of the earth.

An Absurd Fiction

I have made no reference to the continuation of this story - of how Newton, having learnt of the ``more correct measurement of the earth,'' was so affected that he was unable to repeat his calculation. I treat this as absurd. If there is my foundation for the story (and I suppose that most stories have some foundation), it would appear more probable that Newton said something like, ``You do the calculation: you are better at arithmetic than I am.'' Or, even, ``I am sure to make a mistake.'' This would be in accord with Pope's statement (Spence's Anecdotes) that Newton, ``though so deep in Algebra and Fluxions, could not readily make up a common account; and when he was Master of the Mint, used to get somebody to make up his accounts for him.''

Dispute with Leibnitz and Flamsteed

It will be noted that in my discussion on Newton's character I have made no reference to his well-known disputes with Leibnitz and Flamsteed. This is intentional; but I have no wish to ignore these unpleasant occurrences. De Morgan has dealt with them justly, if severely. Agreeing, in the main, with de Morgan, and having nothing new or original to add, I could see no object in repeating what can be so much better read in the original. These episodes have every appearance of being ``straws in the amber''; but let us be charitable, and attribute a good deal to the ``crimson mohair curtains, ``crimson sattees, and thc crimson Harrateen bed-curtains.'' It is notorious that Newton was always extremely sensitive and touchy and had ``a morbid dislike to opposition'' (de Morgan); life in London certainly appears to have had a tendency to increase this ``nervous irritation,'' as I may call it.

A Suggested Line of Research

I have said that I agree ``in the main'' with what de Morgan says about the Flamsteed and Leibnitz wrangles. I fancy, however, that there are letters extant, of which I cannot help thinking de Morgan was ignorant; letters which tend to reflect on Flamsteed's conduct and character, and a knowledge of which would probably have induced de Morgan to have toned down a good deal of what he has said about Newton. This is a question which I think should be ``bolted to the bran''; and anyone (without partisan prejudice) who would study the question carefully would, I fancy, make some interesting discoveries.

Avoiding Contention

There is a very beautiful passage in a letter from Newton to Hooke, dated February 5th, 1675-6, which will illustrate what I have said:

``There is nothing which I desire to avoyde in matters of philosophy more than contention, nor any kind of contention more than one in print; and, therefore, I most gladly embrace your proposal of a private correspondence. What's done before many witnesses is seldom without some further concerns than that of truth; but what passes between friends in private, usually deserves the name of consultation rather than contention; and so I hope it will prove between you and me. Your animadversions will therefore be welcome to me'' (Brewster).

Hero Worship

Alexander Chalmers (Biographical Dictionary 1815) quotes Dr. Johnson as saying of Newton:

``A man who, had he nourished in ancient Greece, would have been worshipped as a Divinity.''

This may or may not be so; I cannot help thinking, however, that there was actually a little worshipping in London!

It would certainly appear that Newton during his latter days was, metaphorically, raised on a pedestal and almost venerated as a divinity. Alexander Chalmers (loc. cit.) refers to Dr. Kiell (Secretary of the Royal Society) as saying:

``If all the philosophy and mathematics were considered as consisting of ten points, nine of these would be found entirely of his discovery and invention.''
Also (loc. cit.) the Marquis de l'Hôpital is quoted as saying:
``Does he eat, drink and sleep like other men? . . . I represent him to myself as a celestial genius, entirely disengaged from matter.''

Lack of Conceit

Human nature (and Newton was very human) cannot endure such an atmosphere without the character suffering. The only wonder is that Newton did not become absolutely conceited - which he never did.

A short reference to a very beautiful incident in the life of that glorious scientific luminary, Michael Faraday, will illustrate my meaning very well.

A Faraday Parable

It is well known that Faraday was not only offered the Presidency of the Royal Society, but that a very strong deputation waited upon him ``to urge him to accept the President's Chair'' (Tyndall, Faraday as a Discoverer, 1868). Faraday begged for a little time for reflection, and Tyndall says that on the following morning, when he called on him, the following conversation ensued :

`` `You would not urge me to undertake this responsibility,' he said. `I not only urge you,' was my reply, `but I consider it your bounden duty to accept it.' . . . This, however, did not seem to satisfy him . . . . `Tyndall,' he said at length, `I must remain plain Michael Faraday to the last, and let me tell you, that if I accepted the honour which the Royal Soclety desires to confer upon me, I would not answer for the integrity of my intellect for a single year.' I urged him no more'' (loc. cit.) [Italics added.]
Comment on this is unnecessary. It appears to me to be almost superhuman.

Dr. Johnson's Tribute

But to return. Rather than bestowing adulation upon Newton as practised by so many writers, I prefer to quote from Dr. Chalrners' biography in the Biographical Dictionary:

``Fontenelle observed that `he was not distinguished from other men by any singularity, either natural or affected'; and Dr. Johnson considered it an eminent instance of Newton's superiority to the rest of mankind `that he was able to separate knowledge from those weaknesses by which knowledge is disgraced; and he was able to excel in Science and wisdom, without purchasing them by the neglect of little things; and that he stood alone merely because he left the rest of mankind behind him, not because he deviated from the beaten track.' ''
and from Halley's inscription of his verses on the Principia:
"Seculi gentisque nostrae decus egregium,"
which we may equally apply to the work and to its author.

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