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Primer: Newton’s Prism Experiments and Theory of Color December 10, 2008

Posted by Will Thomas in EWP Primer.
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Today’s Hump-Day History post is written by frequent visitor Thony Christie, a dedicated amateur historian who “once had a semi-professional background”.  He has approved a few editorial truncations and rephrasings.

Update: Not long after this blog post, Thony started his own blog, The Renaissance Mathematicus.

In 1672 the still relatively young and unknown Lucasian Professor of Mathematics at Cambridge University, Isaac Newton, published his first piece of experimental philosophy: “A Serie’s of Quere’s Propounded by Mr. Isaac Newton, to be Determin’d by Experiments, Positively and Directly Concluding His New Theory of Light and Colours; and Here Recommended to the Industry of the Lovers of Experimental Philosophy, as they Were Generously Imparted to the Publisher in a Letter of the Said Mr. Newtons of July 8.1672”  in the Philosophical Transactions of the Royal Society.  The work became a touchstone in the establishment of the short report of experimental results in a serialized publication as a major means of scientific communication.  The Philosophical Transactions had existed for seven years prior to Newton’s contribution, but had been dedicated primarily to reporting the Royal Society’s regular piecemeal correspondence rather than the systematic presentation of experiments and observations, which was at that time accomplished mainly in the book format.

A sketch by Newton of one of his prism experiments.

A sketch by Newton of one of his prism experiments.

As to the content of Newton’s first publication, it reported a series of simple but elegant experiments with a beam of sunlight and a couple of glass prisms, in which Newton demonstrated that light is not homogeneous and white, but heterogeneous, and made up of different colours each of which has a slightly different index of refraction thereby resulting in the spectrum when refracted by a prism or the rainbow when refracted by raindrops. Previous to Newton, it had been believed that colour was an attribute or property of the objects that were coloured and that the perception of colour was somehow transmitted from the objects to the eye during the process of vision, an idea that went back to Aristotle. It was also believed that the spectrum was produced by white light being somehow dirtied or darkened on passing through the refracting medium. Newton’s paper changed all of this radically.

But not without difficulty. The two leading experts for things optical, at this time, were Robert Hooke in London and Christian Huygens in Paris, both of whom reacted very negatively to Newton’s paper. When asked for his opinion by Oldenburg, the secretary of the Royal Society, Huygens was at first lukewarm and did not appear to see anything new in Newton’s work, implying that he had not really read the paper, but, when pressed, rejected Newton’s theories out of hand. Newton was enraged and in his reply addressed Huygens, a leading figure in European natural philosophy, as if he were addressing a particularly ignorant schoolboy. Huygens said that if the discussion was to be conducted at that level, he would not contribute.

One of Newton’s major problems was that he had used his discoveries to support his own view that light was corpuscular in nature; he argued that the refracting medium imparted spin to a light particle (in the same way as a tennis player imparts spin to the ball), and the different indexes of refraction are a result of the different degrees of spin imparted to the particles of each colour. Both Huygens and Hooke had developed wave theories of light, and it was Hooke who took up the attack.  He interpreted Newton as saying that his theory of colour was dependent on a corpuscular theory of light.  Yet, as he, Hooke, had already philosophically demonstrated that light was propagated in waves, then Newton’s theory must be wrong. This was just the main one of many criticisms that Hooke brought that led to a very tempestuous exchange of letters through Oldenburg over a period of several years.

At first Newton was content to answer, and he even showed that his theory worked equally well for a wave theory of light at the same time producing the best mathematical model for such a theory in the 17th century. During this period Newton worked on a long exhaustive essay on optics covering all of his research work up until this time, which he intended to publish in the Philosophical Transactions as a glorious rebuttal of all of his critics.  However, Hooke did not let up, and Newton was further beset by criticisms from Ignace Gaston Pardies, a highly respected Jesuit scientist living in Paris who was also something of an expert for optics, and a second Jesuit, the Englishman Francis Hall, known as Linus, who lived in Liège. The dispute with Pardies passed off relative quietly, but the one with Linus dragged on for six years, and was continued by his student John Gasgoines after Linus’ death.

Although Linus was not a well-known philosopher, his objections are interesting and significant from a methodological point of view: he complained that he had been unable to repeat Newton’s experiments! This was not an isolated incident as the same thing occurred to Italian Newtonians at the beginning of the 18th century. In the case of the Italians, it turned out that the problem lay in the quality of the glass prisms that they were using and when they replaced them with better quality glass they were able to achieve the same results as Newton.  One can assume that something similar happened in the case of Linus, but we will never know.

The results of this mass of criticism were fairly monumental.  Newton’s patience, never very good at the best of times, gave out. He withdrew the extended optics essay that he had been writing and refused to have any more direct dealing with the Royal Society until 1704.  He never established a relationship with Huygens. The feud with Hooke was patched up, only to break out again in the 1680s when Hooke accused Newton of having stolen the inverse square law of gravitation from him (but that, as they say, is another story).

In 1703 Hooke died and Newton extracted his revenge.  He became active in the Royal Society and was immediately elected its president in 1704, from which position he prevented the publication of Hooke’s posthumous papers (and even is rumoured to have had his portrait burned). In the same year he finally published that long essay, to which Hooke’s criticism had driven him, as the first section of his book Opticks (which became a great classic of the scientific literature).

In the Bible the rainbow is a symbol of peace following a deluge; for Newton, unweaving the rainbow proved to be the prelude to a storm.

Literature: For all things Newton the best place to start is Richard Westfall’s masterpiece Never at Rest: A Biography of Isaac Newton [1980], a book that deserves a place in Will’s list of canonical literature. On the intricacies of 17th century optical theories and the disputes between their proponents the best source is A.I. Sabra’s Theories of Light from Descartes to Newton [1967].

NB from Will: On the difficulties of replicating Newton’s prism experiments and the controversies surrounding Newton’s claims, also see Simon Schaffer’s classic “Glass Works: Newton’s Prisms and the Uses of Experiment” in the 1989 volume
The Uses of Experiment.

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Comments»

1. Tom - December 10, 2008

Great post, though it is probably a bit too strong to say that Newton never had a relationship w. Christiaan Huygens. Newton had sent the older man a copy of Principia on publication (which enabled Huygens to reassure John Locke of the validity of the math of Newton’s demonstrations.) Westfall reports that the two probably first met face to face at the Royal Society meeting of June 12 (Newton was not entirely estranged from the Society before Hooke’s death, and was friends with at least two Presidents — Pepys and Wren after the debacles of the ’70s). The two also met in July at Hampton Court, and Huygens supported Newton in his attempt to gain royal patronage.

That was close to about it — and a modest correspondence and a couple of encounters do not a deep friendship make. But Newton’s regard for Huygens was of a vastly different quality than his loathing for — and much greater contact with — Robert Hooke.

But again — thanks for the post. Much stuff in it elegantly and compactly delivered.

2. Tom - December 10, 2008

BTW — I didn’t mean to hide behind internet anonymity. The comment above comes from Tom Levenson.

3. Thony C. - December 15, 2008

Thank you for your kind words, Thom, to which I should have responded more quickly. Any elegance that my post has is entirely due to Will’s astute and judicious editing that proves that you can (almost!) make a silk purse out of a sow’s ear. My point on Huygens is that a scientific correspondence never developed between them as existed, for example between Huygens and Leibniz; in which, by the way, he described the Principia as “absurd”. (Of course Newton sent him a copy of his Opus magnum, after all Huygens was one of only a handful of scientists in Europe who would have been able to understand it.) On the subject of their meetings when Huygens went to England in 1689 Westfall writes; “No continuing correspondence resulted from their meeting, however”.

Through your comment here I have discovered your own interesting blog that has now been added to my early morning stroll through the Blogasphere.
ThC.

4. Will Thomas - December 15, 2008

I should also point out that I chopped Thony a bit on this point; he was more clear in the original that he was lamenting the lack of productive scientific correspondence between them. Also, thanks for the contribution, Thony. Thanks to your friends over at Evolving Thoughts, our Blog Stat-o-meter was way above average for this post.

5. The Giant’s Shoulders #6 « Rigorous Trivialities - December 15, 2008

[…] quantum theory. More on the events surrounding Newton’s experiments at the relevantly named Ether Wave Propaganda […]

6. notedscholar - December 15, 2008

Yuck. It was a sad, and racist day when “black” was deemed “not a color.”

NS
http://sciencedefeated.wordpress.com

7. Advances in the History of Psychology » Blog Archive » “Giant’s Shoulders” #6 Is Up - December 27, 2008

[…] piece on Isaac Netwon’s 1672 experiments with light, prisms, and color at Ether Wave […]

8. Refraction, refrangibility, diffraction or inflexion « The Renaissance Mathematicus - March 14, 2010

[…] that followed Newton’s paper on refraction and the nature of light (which I have discussed here) one of the disputants, the Jesuit Ignace Gaston Pardies, inquired whether Grimaldi’s recent […]

9. Will Thomas - December 5, 2010

This post — long the most popular on this blog — has now reached 3,000 page views. Happy 3K Thony C!

10. Thony C. - December 5, 2010

I don’t believe it!

11. Will Thomas - May 25, 2011

More popular than ever (possibly related to renaming it a “primer”?), this post now has 4,000 page views.

12. Thony C. - May 28, 2011

Enough already!

13. Monday blast from the past #13: Newton’s Early Optics | The Renaissance Mathematicus - February 6, 2012

[…] experiment with a prism and his theory of colour is today’s ‘Monday blast from the past’.  Newton’s Prism Experiments and Theory of Colour Like this:LikeBe the first to like this […]

14. Kirsten Walsh - October 9, 2012

Hi Thony,

I just came across your post this morning – I enjoyed reading it.

It might be a little late to point this out, but Newton’s first paper on his theory of light appeared in the 19 Feb 1671/2 issue of the Phil Trans: http://rstl.royalsocietypublishing.org/content/6/69-80/3075.full.pdf+html The ‘experimentum crucis’ you mention (from which he concludes that white light is heterogeneous) begins at the bottom of page 3078 of this paper.

The ‘Queries’ paper you mention came after Newton had already corresponded with Pardies and Hooke. It’s a very interesting paper, but it’s not the one in which he describes his early experiments using prisms.

Cheers,

Kirsten

Thony C - October 11, 2012

Thanks Kirsten. I have to admit I find the situation quite funny.

15. Oh Boy! I done screwed up real bad and nobody noticed! | The Renaissance Mathematicus - October 11, 2012

[…] is funny about this situation is that I posted my piece on 8th December 2008 and since then it has been read by several thousand people and nobody noticed the glaring error […]

16. Grumpy old astronomers behaving badly or don’t just blame Isaac! | The Renaissance Mathematicus - March 20, 2013

[…] that it undoubtedly is this paper met an avalanche of criticism that I have dealt with in some detail here. Leading the pack was Robert Hooke who considered himself the leading authority on all matters […]

17. Did Edmond tells Robert to, “sling his hooke!”? | The Renaissance Mathematicus - March 31, 2014

[…] in Cambridge. Although Newton declined to have anything more to do with the Royal Society following the numerous disputes, not just with Hooke, following the publication of his theory of light in 1672 he certainly did not go to pieces, giving as good as he got and he was not hiding in Cambridge but […]

18. Preach truth – serve up myths. | The Renaissance Mathematicus - January 7, 2015

[…] Newton did do between 1666 and 1672 was to conduct an extensive experimental programme into physical optics, in particular what he termed the phenomenon of colour. This programme resulted in the construction […]

19. Isaac and the apple – the story and the myth | The Renaissance Mathematicus - May 12, 2016

[…] mechanics for the meantime and moved onto optics, where his endeavours would prove more fruitful, leading to his discoveries on the nature of light and eventually to his first publication in 1672, as well as the construction of his reflecting […]


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