Virtual Recreation of Newton’s ‘Experimentum Crucis’ Two Prism Experiment

Dispersion of light through two prisms rendered in Luxrender

Well, a virtual recreation with a bit of license. This started as a test to see if the physically based render program Luxrender  can make a believable simulation of white light passing through a prism.  Unbiased render engines like Luxrender send out very many virtual photons and calculate their paths according to physical laws, and as the ray-tracing algorithm includes colour dispersion, it should work in theory.

Throw a second prism into the scene, and we have Isaac Newton’s ‘Experimentum Crucis’: one of a series of experiments performed by Newton in 1666 and reported in a letter to the Royal Society in 1671 (1), showing how white light is composed of a range of colours separable by a prism.  He demonstrated the colours were a property of the light, not the prism, by using a slit to isolate an individual colour from one prism, and passing it through a second where no further separation of colours occurred – the second prism just refracted the single colour to one side.  Here is Newton’s own drawing of his two-prism experiment.

Experimentum Crucis
Experimentum Crucis

My distances and prism sizes are not accurate, but the simulation still works.   Also, while Newton used the sun as a light source, sometimes passed through a slit before the first prism or focused through a lens as above, my source is a small rectangular surface radiating in all forward directions, but with a collimating tunnel placed in front of it.  If the light source is too ill-defined or unfocused, in both reality and in the simulation, the separation in the spectrum can look reasonable superficially, but actually comprise a series of fuzzy overlapping spectra.   The result being, when I ran this without the collimator, the green band split into further discernible colours.   That said, it’s worth remembering that while Newton reported seeing seven colours, the actual spectrum is a continuum of wavelengths, so a single colour will in fact be made of a range of further dispersible shades – we just don’t discern it.

Here is a close-up of the isolating slit and the green spectral ‘line’ deviated but not dispersed by the second prism.  I’ve also in this picture turned out the background light used solely for dramatic effect in the first picture.

Dispersion through two prisms

And here are wireframe pics of the layout (scene created in Poser and linked to Luxrender via Reality):




An interesting feature of this type of modelling is the need for a so-called Tone Mapping process, by which the multiple wavelengths for which the ray-tracing maths must be repeated to simulate dispersion is translated into the red, blue, and green (RGB) that the computer monitor can understand to display the result.

Also worth noting the limitations to this sort of progam as a virtual optical bench.  Luxrender is not, for example, up to calculating the quantum probability amplitudes necessary to simulate interference as seen in the double slit experiment.



(1)  doi: 10.1098/rstl.1671.0072 Phil. Trans. 1 January 1671 vol. 6 no. 69-80 3075-3087   (link to Royal Society Publishing)

Also of interest:

Experimentum Crucis
J. A. Lohne
Notes and Records of the Royal Society of London, Vol. 23, No. 2 (Dec., 1968), pp. 169-199
Published by: The Royal Society

The Sun Ain’t Gonna Shine (Anymore) – Maybe. Polar Exploration and the Mysterious Novaya Zemlya Effect

Sun's image distorted and elongated by atmospheric refraction ©Tim Jones
Sun’s image distorted and elongated by atmospheric refraction ©Tim Jones

A Polar Phenomenon

In May 1915, as Ernest Shackleton and the crew of Endurance entered their fourth month trapped in ice on the Antarctic’s Weddell Sea, the ship’s navigator added to the gloom by declaring the Sun would be absent from the sky for the next seventy days.   You expect this at above 75° South; but then on the 8th of May something strange happened.  The Sun reappeared – several times:

The sun, which had made “positively his last appearance” seven days earlier, surprised us by lifting more than half its disk above the horizon on May 8.  A glow on the northern horizon resolved itself into the sun at 11 a.m. that day.  A quarter of an hour later the unseasonable visitor disappeared again, only to rise again at 11.40 a.m., set at 1 p.m., rise at 1.10 p.m.. and set lingeringly at 1.20 p.m.

Ernest Shackleton, 19151


Shackleton understood the effects of atmospheric refraction, that temperature and density differences can bend light – especially near the horizon.   At sunrise and sunset the disk of the Sun can appear distorted: lengthened or flattened, or displaced from its true position in the sky – where Newton put it.

Endurance in Weddell Sea
Ernest Shackleton made his observations from the Endurance while frozen in the Weddell Sea (the bay top left)

Mariners knew about the phenomenon, and referenced standard refraction tables to correct sextant readings in navigation; but the system broke down below about 6 degrees, where refraction increased rapidly and non-linearly.

How atmospheric refraction can make the Sun visible when it's still below the horizon ©Tim Jones
How atmospheric refraction can make the Sun visible when it’s still below the horizon ©Tim Jones

In this case, as Shackleton recorded in his journal, the Sun was 2 degrees and 37 minutes (2°37′) from its true position, 2 degrees more than any refraction table prediction.  Plotting position from this observation would place the Endurance 120 miles from its actual location.

What Shackleton experienced was an extreme case of atmospheric refraction known as the Novaya Zemlya effect, first reported in 1597 by Gerrit De Veer2 , one of the crew on Willem Barent’s third voyage to discover a north-east passage.  Obliged to hunker down for the polar winter in a safety hut or ‘Het Behouden Huijs‘ built on the Novaya Zemlya island chain north of Russia, De Veer reported the return of the post-winter Sun a whole two weeks before it should have been visible; it was in fact 5°26’ below the horizon.  The same thing happened two days later, the Sun still, by the book,  4° below the horizon.

Novaya Zemlya
Map depicting Willem Barents three voyages to discover a North East Passage, showing the Novaya Zemlya islands (Wikipedia)

novaya1The Novaya Zemlya effect occurs in Arctic regions where tracts of cold air remain uniquely stable over hundreds of kilometers, creating a special instance of a  meteorological temperature inversion.  The distortion, powerful enough to bend light through four or five degrees, can make celestial bodies like the Sun or Moon appear wholly above the horizon when they are physically below it.  (If you imagine looking at the horizon, five degrees is the same as ten Suns or Moons in a row.)

For hundreds of years, Gerrit De Veer’s solar observations, and equally his report of a curiously displaced conjunction of the Moon and Jupiter, were not believed.  They said he must have counted the days wrong, or used the wrong sort of calendar.  It took the corroborating reports of polar explorers like Shackleton and, as recently as 2003, ray-tracing simulations3 using contemporary atmospheric data, to vindicate De Veer fully.

Modern almanacs still include refraction tables. (HM Nautical ALmanac Office)
Modern almanacs still include refraction tables. (HM Nautical ALmanac Office)


Time Travel with Starry Night

I’ve set up my own simulations of the celestial events reported by Shackleton and De Veer using the planetarium software Starry Night.  The program can’t reproduce the ray traced refraction effects modeled by van der Werf et al3 – whose validity I’m not equipped to comment on by the way, but it’s still satisfying to check the published numbers and get a feel for what the events looked like all those years ago.





Shackleton’s Solar Observation

First up, the view from the Endurance in 1915:

View from Weddell Sea (Lat. 75 degree 23 mins S Long. 42 degree 14 mins W) 8th May, 1915, 1:20pm (UT) ©Tim Jones, Starry Night Software
View from Weddell Sea (Lat. 75 degree 23 mins S Long. 42 degree 14 mins W) 8th May, 1915, 1:20pm (UT) ©Tim Jones, Starry Night Software

The horizon terrain here is generic Starry Night; apart from being icy-white, the true horizon would run perpendicular to and cross the graduated white Meridian line at zero (0) degrees.  The green line is the Ecliptic.  Things are clearer for our purposes, if less romantic, if we turn off the daylight effect and fancy terrain and zoom in a bit.  It’s now clear the Sun was below the horizon when Shackleton reported seeing it: i.e. with reference to the Meridian on the left, the Sun looks about two and half degrees below the zero degree mark (Shackleton’s 2°37′):

View from Weddell Sea (Lat. 75 degree 23 mins S Long. 42 degree 14 mins W) 8th May, 1915, 1:20pm (UT). With generic landscape and daylight effect turned off ©Tim Jones, Starry Night Software


Gerrit De Veer’s Solar Observation

Willem Barent’s crew, marooned 300 years earlier at the opposite end of the planet, made their observations from the ‘Behouden Huijs‘ at coördinates 76° 15.4′ North 68°18.6’ East, Novaya Zemlya.  This view from the Huijs at 7 o’clock on the morning of 24th January 1597, shows the Sun was firmly below the horizon when Gerrit De Veer observed it – a whole 5°26′ below (horizon is perpendicular to the zero mark on the white Meridian line, green line is the Ecliptic):

Gerritt De Veer sunrise
View from the rescue hut on (Lat. 76 degree 15.4 mins N Long. 68 degree 18.6 mins W) 24th Jan, 1597, 7:00 am (UT). ©Tim Jones, Starry Night Software


Gerrit De Veer’s Moon-Jupiter Conjunction

The Moon-Jupiter conjunction reported by De Veer physically happened at 0:14 UT on 25th January 1597 (there is a small error in the 0:24 UT time given in the contemporary tables by Scala that De Veer used).   Like astronomers today, De Veer identified the moment of conjunction as the time when a line drawn along the shadow separating light from dark on the moon’s surface, the terminator, pointed directly at Jupiter, as in this photograph I took of the Moon-Jupiter conjunction of 21 January 2012:

Moon and Jupiter, 18:45, 21.01.2012, Los Angeles ©Tim Jones
Moon and Jupiter, 18:45, 21.01.2012, Los Angeles ©Tim Jones

 This is the Starry Night simulation of the De Veer conjunction:

De Veer's moon jupiter conjunction
Moon-Jupiter conjunction, 0:14 (UT) 25th Jan,1597. Location: the rescue hut on (Lat. 76 degree 15.4 mins N Long. 68 degree 18.6 mins W) ©Tim Jones, Starry Night Software

The Moon is barely above the horizon and Jupiter is below it (again, reference the zero on the white Meridian line).

Gerrit De Veer saw this view, but over an hour after it happened: i.e. at 01:27 UT not 00:14 UT.  As van der Werf’s analysis explains, De Veer reported the conjunction at 6 a.m. local time, which was 4:33 hours ahead of UT.  Such was the unbelievable power of the Novaya Zemlya effect to make this happen that few indeed believed it.   De Veer learned about the conjunction from his copy of the Ephemerides of Josephus Scala which gave times for Venice.  Here we pick up the story in De Veer’s own words and the spellings of his 1609 translator William Phillip:

Whereupon we sought to knowe when the same coniunction should be ouer or about the house where we then were; and at last we found, yt the 24 day January was the same day whereon the coniunction aforesaid happened in Venice, at one of the clocke in the night [= 1 in the morning of 25th Jan], and with vs in the morning when ye sun was in the east: for we saw manifestly that the two planets aforesaid approached neere vnto each other, vntill such time as the moone and Jupiter stood ouer the other, both in the sign of Taurus, and that was at six of the clocke in the morning;at which time the moone and Jupiter were found by our compas to be in coniunction, ouer our house..
Gerrit De Veer 1597

Yet ray tracing the scenario 400 years later, with Jupiter two degrees below the horizon and the Moon just above it at  conjunction, shows that atmospheric conditions raised Jupiter’s apparent position disproportionately to that of the Moon.  Moreover, the simulation reproduced what De Veer saw at the time he saw it: a conjunction visible to him at around 02:00 UT.  The ray tracing team made a further minor adjustment for the Equation of Time effect, which brought their estimate of when the conjunction was visible to De Veer as 06:20 local time, which is impressively close to his 06:00.)

Apparent position of Jupiter and the Moon after allowing for atmospheric refraction. Diagram reproduced from analysis by van der Werf et al, 2003 (reference 2)
Apparent position of Jupiter and the Moon after allowing for atmospheric refraction. Moon is double actual size for clarity. Diagram reproduced from analysis by van der Werf et al, 2003 (reference 3)

One More Thing

Although Gerrit De Veer’s vindication now seems complete, there was one little alarm bell went off during my research, and that concerns De Veer’s reference to both the Moon and Jupiter being in the constellation of Taurus at the time of conjunction.  Zooming in to see the 1597 conjunction against modern constellation boundaries puts it well into Aries.  So what gives?

Modern constellation boundaries. Moon-Jupiter conjunction, 0:14 (UT) 25th Jan,1597. Location: the rescue hut on (Lat. 76 degree 15.4 mins N Long. 68 degree 18.6 mins W) ©Tim Jones, Starry Night Software

Maybe the constellation boundaries have changed; let’s have a look at Albrecht Dürer’s beautiful star chart from 1515.  The belly of the bull tucks a little further under the ram than in modern charts, but the conjunction is still firmly in Aries. 

Star chart of the northern skies, Albrecht Dürer, 1515, Nuremberg.
Star chart of the northern skies, Albrecht Dürer, 1515, Nuremberg.

Maybe the Moon made the stars in Aries harder to see that night, so instead De Veer focused on the sparkling Pleiades and Hyades clusters in Taurus; I’d probably do that if I were standing in a freezing Arctic wasteland staring at the sky at six in the morning.  I later discovered Charles Beke4 in a 19th century analysis of the William Phillip translation also noticed the discrepancy.  He points out a retrogression of the equinoctial points – the places where the celestial equator intersects the ecliptic – has since De Veer’s day shifted the positions of the constellations in terms of longitude and latitude relative to those references; but that rather suggests in his write-up De Verre placed the conjunction in whatever constellation the numbers dictated, rather than where he saw it?  Still a bit of a mystery to solve then – at least in my mind.  


  1. E. Shackleton, South: The Story of Shackleton’s Last Expedition 1914–1917, MacMillan, New York, 1920
  2. Gerrit De Veer, The Three Voyages of William Barents to the Arctic Regions (1594, 1595 and 1596). London, 1876 (translation of 1609 original).
  3. Gerrit de Veer’s True and Perfect Description of the Novaya Zemlya Effect, 24-27 January 1597, Siebren Y. van der Werf, Günther P. Können, Waldemar H. Lehn, Frits Steenhuisen, and Wayne P. S. Davidson; Applied Optics, Vol. 42, Issue 3, pp. 379-389 (2003)
  4. Charles T. Beke, The Three Voyages of Willem Barents to the Arctic Regions 1594, 1595 and 1596 by Gerrit de Veer, 2nd ed.William Phillip, trans., Hakluyt Society, London, 1876 (Page 147)


Erasmus Darwin’s Birthday 12th December 1731

We shouldn’t let the day pass without a thought for Erasmus Darwin, whose birthday it is today.

Erasmus Darwin by Joseph Wright of Derby 1792 (WikiCommons)
Erasmus Darwin by Joseph Wright of Derby 1792 (WikiCommons)

Erasmus was born on 12th December 1731, at Elston Hall in Nottinghamshire.

During his seventy year span, Charles’s illustrious grandfather made more and varied contributions to the world of ideas than many today would guess – if they’ve even heard of him.

Erasmus is also of course the spirit behind Zoonomian; here are a couple of earlier posts that sum up his achievements and involvements:

The Other Darwin Genius

Unweaving the Waterfall – Erasmus Darwin at Vauxhall Gardens  (per my  talk at the Foundling Museum in June)

Erasmus Darwin House in Litchfield (Photo:Tim Jones)
Erasmus Darwin House in Litchfield (Photo:Tim Jones)

Erasmus set up his medical practice in Litchfield, where he lived from 1756 to 1781.  His house, now the Erasmus Darwin House Museum, is close to the magnificent cathedral, and well worth a visit.  (Samuel Johnson also lived in Litchfield, so you can visit his house while you’re there.)

Litchfield Cathedral (Photo: Tim Jones)

Erasmus spent the last two years of his life at Breadsall Priory, where he died on April 18th 1802, aged 70.

Breadsall Priory, where Erasmus Darwin died in 1802 (Photo permission S.Klinge)

To round off, here are three excellent and recent videos on Erasmus courtesy of History West Midlands:

Erasmus Darwin at The Heart of The Litchfield Enlightenment

The Litchfield Enlightenment

Erasmus Darwin The Scientist


A Visit to Great Malvern and Annie Darwin’s Grave

Anne Darwin's Grave at Malvern Priory (Photo:Tim Jones)
I suspect Darwin would be happy to see squirrels running over his daughter’s grave. ‘Annie’ Darwin’s Grave at Malvern Priory (Photo:Tim Jones)

Until last week, I’d only seen the Worcestershire town of Great Malvern from the air.  Flying light aircraft in the nineties, one of my favourite sightseeing tours was to head out west from my local airfield near Stratford, turn south over Worcester racecourse towards the Malvern Hills, and watch the sun set over the waters of the Severn estuary.

The ‘Malverns’ are odd.  An isolated stretch of peaks, nine miles long and 1394 feet at the highest point.  Rising half way up the Eastern side, like a carpet pushed up against a wall, is the town of Great Malvern.  In an aeroplane it’s a nice spot to practice steep-banked turns, while distracting your passenger with one of England’s greener and pleasanter views.   We mostly got cloud and rain last week – so here’s a view in brighter conditions:

Malvern Hills (WikiCommons)
Malvern Hills (WikiCommons)
Malvern's gas lamps may have inspired the opening to C.S.Lewis's Narnia (Photo:Tim Jones)
Malvern’s gas lamps may have inspired the opening to C.S.Lewis’s Narnia (Photo:Tim Jones)

Amongst the famous folk associated with Malvern are C.S.Lewis and J.R.R.Tolkien, whose experiences walking together in the hills, it’s said, fed into their fantasy worlds.  For sure, I can see how elves and dwarves might emerge from the cloudy scrumpy cider we sampled at the Unicorn pub – the authors’ favourite after-hike watering hole.

The composer Sir Edward Elgar was a local, and rests with his wife in nearby Little Malvern.

And the private school Malvern College gave many influential political, military, and media people their educational start – including journalist Jeremy Paxman; but not so many scientists or engineers it seems.

That said, it’s a scientist, Charles Darwin, that I associate most strongly with Malvern.  A regular visitor from 1849, Darwin made the two-day journey to Malvern to partake of the town’s popular water therapy, hoping it might relieve the chronic vomiting and headaches that plagued him for much of his life (and caused some now think by Chagas’s disease1 contracted on his Beagle voyage to South America).  He would later return with his seriously ill daughter Annie.

Ten year old Annie had weakened from scarlet fever over the previous two years, and, with her condition worsening, on 24th March 1851 Darwin made the trip with her to Malvern and Dr James Gully.

Pioneers of hydrotherapy, or hydropathy as they called it, Gully and his colleague James Wilson set up the first of several specialist clinics in the town.  Like other spa towns in England, the geographic and economic growth of Malvern was largely driven by the perceived value of its natural waters.

First Water Cure Establishment in Great Malvern (Photo:Tim Jones)
First Water Cure Establishment in Great Malvern (Photo:Tim Jones)
Plaque to the first purpose built water cure establishment (Photo:Tim Jones)
Plaque to the first purpose built water cure establishment (Photo:Tim Jones)

Despite Gully’s efforts, Annie was beyond any water-cure, and Darwin was to leave her in Malvern, permanently, a month later.   She died at their lodgings in Montreal House on the Worcester Road, and is buried in the grounds of nearby Great Malvern Priory – literally a stone’s throw from our hotel.  Gully described Annie’s condition at death as a “Bilious fever with typhoid character”2; it’s now thought more likely she died from tuberculosis.

Anne Elizabeth Darwin, 1848 (Wikipedia)
Anne Elizabeth Darwin, 1848 (Wikipedia)
House on Worcester Road, Great Malvern, where Anne Darwin died (Photo:Tim Jones)
Montreal House on Worcester Road, Great Malvern, where Charles and Anne lodged with Eliza Partington, and Anne Darwin died on 23rd April 1851 (Photo:Tim Jones)
Plaque to Charles and Anne Darwin (Photo:Tim Jones)
Plaque to Charles and Anne Darwin (Photo:Tim Jones)
Great Malvern Priory (Photo:Tim Jones)
Great Malvern Priory (Photo:Tim Jones)
'Annie' Darwin's gravestone at Great Malvern Priory (Photo:Tim Jones)
‘Annie’ Darwin’s gravestone at Great Malvern Priory (Photo:Tim Jones)

From a modern perspective, Gully’s water treatments were doomed to failure.  The enthusiastic Gully might wrap a patient in wet sheets, subject them to heavy douches from above and below, or enroll them for a course of ‘spinal washing’.

The core water treatment might be augmented with anything from hill walks to homeopathy, to clairvoyancey, to what amounted to a light baking under oil lamps.  Hydropathy’s enthusiastic adoption and questionable effectiveness groups it with the electrical and magnetic treatments popular with Victorian physicians at the time, eager to apply new insights on nature, however misguided, to human well-being.

Some of the water treatments Gully and Wilson would have used. From: Hydropathy, or, The water-cure: its principles, modes of treatment. Joel Shew, Wiley & Putnam 1844 (Ref.5)
Some of the water treatments Gully and Wilson would have used. From: Hydropathy, or, The water-cure: its principles, modes of treatment. Joel Shew, Wiley & Putnam 1844 (Ref.3)

Perceived benefits were most likely due less to the watery aspects of Gully’s therapy, and more to the generally healthy context of their delivery.  Plain eating, abstention from alcohol, and daily exercise in a calming environment could do a lot for a bloated Victorian gentleman.  But that didn’t stop Gully and like-minded advocates publishing elaborate treatises and supposedly affirmative case studies4 directly linking water therapy to the cure of all kinds of disease.

Clairvoyance - after George CruikshankDarwin hung in with Gully’s ideas for years before concluding any benefit was limited and purely psychosomatic.  He never bought into homeopathy, and seems to have gone along with the more spiritual add-ons from Gully’s palette to keep their relationship.  Darwin was open to new ideas, but he always judged them against the standard of reason.

Annie was a special favourite among Darwin’s children, and her death took a lasting toll on his mental state.  The poignant memorial he wrote to Annie is here at the Darwin Correspondence Project5

Annie’s story also formed the background to the movie Creation (my earlier review here), with Paul Bettany as Darwin, Jennifer Connelly as his wife Emma, and Bill Paterson as Dr Gully.  The film, based on Darwin’s descendent Randal Keynes’s book Annie’s Box, is worth watching if you can forgive a bit of historical license-taking (for one thing, Darwin’s other children don’t age through a series of flashbacks involving Annie).  Also, note that the town where they shoot the Malvern scenes, which I can now vouch has the feel of the place, is actually Bedford-on-Avon).



1. The Mystery of Darwin’s Ill Health.  The Darwin Correspondence Project

2. Darwin, Desmond and Moore, Pub.Michael Joseph, 1991, p.384

3. Hydropathy, or, The water-cure: its principles, modes of treatment, &c., illustrated with many cases : compiled chiefly from the most eminent English authors on the subject. Shew, Joel, 1816-1855. New York : Wiley & Putnam, 1844. Link to text at U.S. Library of Medicine here.

4. The Water Cure in Chronic Disease.  James Manby Gully, M.D., 1850, John Churchill, London

5. The death of Anne Elizabeth Darwin.  The Darwin Correspondence Project

6. Note on the IHS monogram here at History from Headstones


Clairvoyance cartoon from George Cruikshank’s Table Book, 1845

The Darker Side of (some) Scientists

Jekyll and Hyde Title

I guess at times we all put up a mask in public.  We might even have a bit of a dark side kept under wraps most of the time.  But there’s something extra-disturbing when our heroes show a side to them we never knew, especially when it’s at odds with the comfortable stereotype they’ve come to represent.

Take doctors for example: helpful, trustworthy folk, blessed with skills in beneficent care and correcting surgery.  Yet Lars Tharp, talking about Hogarth and medicine at the Foundling Museum yesterday, reminded me of at least one medical man with a shadow over him, and a dark side literally demarcated by the geography of his home.

Hogarth’s Reward of Cruelty. Anatomising a criminal, 18th century style

Those who have read Wendy Moore’s biography The Knife Man will know I’m talking about John Hunter – traditionally tagged with the strap-line ‘Father of Modern Surgery’ – as he doubtless was.

That was almost an accolade he could celebrate in his own lifetime, within the genteel and elegantly decorated reception rooms of his Leicester Square mansion.  Yet the learning behind Hunter’s reputation wasn’t gained in his salon, but in the less well publicised back rooms and tiered operating theatre, fed by grisly subjects for anatomy arriving all too timely through the back entrance on shabby Castle Street.

John Hunter
John Hunter

Hunter had cleverly bought the house onto which his Leicester Square residence backed, and built his museum and operating theatre between the two – creating separate worlds.

Not surprisingly, scholars credit Hunter’s situation as the inspiration for Robert Louis Stevenson’s novel Jekyl and Hyde.

Incidentally, Hunter was also in his day the top expert on venereal disease, and it’s thought likely he intentionally infected himself with syphilis via his penis for the sake of research.  So despite his  unconventional sourcing strategy for bodies, at least he wasn’t selfish.

Tharp mentioned Hunter only in passing, but a further remark he made puts me in mind of another scientist with a dark side – Isaac Newton, no less.

Isaac Newton
Isaac Newton – hanging judge

The Newton we imagine sitting under a tree, watching apples drop, benevolently ruminating his prisms and calculus, is a far cry from the Master of the Mint Isaac Newton, who doggedly pursued forgers and clippers (they cut bits of valuable metal off coins to sell) to a horrifying death at the Tyburn gallows.  (There’s an excellent account of Newton’s life at the mint in Thomas Levenson’s Newton and the Counterfeiter).

Tharp’s case didn’t implicate Newton personally, but dealt with the particularly harrowing story of a mother found guilty of clipping and awaiting execution at Newgate, pleading with the Foundling Hospital to take care of her child.

Burnt at the stake for clipping coins - Elizabeth Wright
Another clipping offender (The Newgate Calendar)

Her child was saved, but she went on to be burned at the stake all the same; think about that next time you deface the coin of the realm steadying a wonky table leg with a 2p piece (do your own research as to the true present-day hazard of this heinous sin).

So what other scientists’ dark secrets have come out through history to muddy their fantasy image.

Nice guy – some of the time.

There’s Einstein: a nice old guy who wouldn’t harm a fly, right?   Wrong –  at least as far as his family were concerned.  Einstein cheated on his wife, set out unreasonable conditions for their marriage to continue, and paid little attention to his children.  And while we accept Einstein was human like the rest of us, that’s somehow more information than we want to hear.

There’s often a conflict in the minds of scientists who choose to do war work: like building bombs, weapon systems, or other enablers of physical destruction; and there’s still a debate around the social responsibility scientists should bear for the outcomes of their work (although I sense it’s more settled that scientists should indeed feel that obligation).  Closer to home, as a humble chemical engineer in peacetime 1980s Britain, I lacked the opportunity or temptation to get conflicted in that way, but, for sure, the most interesting and rewarding jobs for my physics and electronics buddies were defence related.  I guess Robert Oppenheimer, reluctantly self-styled Destroyer of Worlds and leader of the atomic bomb Manhattan Project, is the text-book example in this category, although if there’s one guy truly qualified for the E-word on that team it’s probably giddy hydrogen bomb fan Edward Teller.

Fritz Haber
Haber – vilified

Fritz Haber is another example.  The Haber process for making ammonia was hugely useful and constructive in the manufacture of fertiliser.  But Haber’s dark association with poison gas manufacture for Germany in the first world war – captured in Tony Harrison’s play Square Rounds – caused his vilification to this day.

It’s an imperfect comparison, but as a scientist whose work ultimately saved millions of lives – through the food produced using ammonia fertilisers, but at the cost of lives lost to gas and explosives, Haber shares some common ground with surgeon William Hunter.  How much faster did surgery move along because society, with a bit of convenient blind eye turning, allowed Hunter access to the bodies he needed?  (Related to this idea, I’ve most recently been intrigued as to where we’d be had some of the more questionable early twentieth century work on brain surgery not gone ahead – as it for sure wouldn’t today.)

What this comes down to is that scientists are just people after all:  some pretty nice, some about alright, and some pretty rotten.

On a brighter note, having multiple facets to your sparkling intellect can also be a good thing.

Astronomer William Herschel’s (1738-1822) tale of confliction is a relatively happy one that I think made his life more fulfilling.

Herschel discovered Uranus and built fabulous ground-breaking telescopes.  But he was also a professional organist and competent composer, whose first love – and bread and butter for much of his life – was music.

And it stayed with him; Herschel’s cheery ‘Echo Catch’ was performed at the pleasure gardens in Bath only a year before he discovered the mysterious seventh planet. For other good stuff Herschel got up to,  see this earlier post.

I’m sure there are loads more examples of scientists whose dark side has come to light through some sordid revelation.  But these are the ones who sprang to mind; maybe I’ll add more later.  Feel free to volunteer candidates – especially if they’re still living.

Right!  Two in morning.  Now where did I put my cape and sword-stick.


References & further reading

1. The Knife Man, Wendy Moore, Bantam Press 2005

2. Newton and the Counterfeiter, Thomas Levenson, Faber & Faber, 2009

3. The Other Side of Albert Einstein, Physics World, 2005

4. Square Rounds, Tony Harrison, Faber & Faber, 2003

5. The Georgian Star. Michael Lemonick, Atlas, 2008

6. Article on Fritz Haber here at

Charlie’s Rose

Charles Darwin wrote about roses in his The Variation of Animals and Plants under Domestication, but I’m guessing he didn’t expect a variety would be named in his honour.

Charles Darwin rose in the grounds of the Huntington Estate, San Marino (Photo:Tim Jones)
Charles Darwin rose in the grounds of the Huntington Estate, San Marino (Photo:Tim Jones)

I stumbled upon these today in the gardens of the Huntington (Library, Art Collection, Botanical Gardens) Estate in San Marino.    According to this rose dealer, the variety is hardy, with a ‘strong and delicious fragrance that varies between a soft, floral Tea and almost pure lemon according to weather conditions’.  Sounds like it would be right at home at Darwin’s former home in Kent (where it may indeed be for all I know).  Whatever.  Compared to some of the other blooms on show today, most of which were wilted or entirely dropped off in the December chill, these Darwin specials are putting up a pretty good show.

Charles Darwin rose (Photo:Tim Jones)Charles Darwin rose tag (Photo:Tim Jones)

Contrary to popular opinion, the British aren’t all manic gardeners, and I wouldn’t ordinarily get over-excited about a rose garden.  But spurred on by the father of evolution, I scouted out a few more scientifically inspired varieties.  Marie Curie is hanging in there but looking the worse for wear:

Marie Curie rose (Photo:Tim Jones)And one Archimedes would have approved of:

Eureka rose (Photo:Tim Jones)

Leonardo needs some tidying:

Three for the astronomers:











The geologist’s choice looks the part:





Arctic explorers only:

Then a few others that aren’t really scientific but I find interesting, intriguing or odd – I didn’t expect to find ‘Pimlico’ and the ‘Radio Times’ in California – included:

Whisky Mac, Anne Boleyn, Radio Times, Brilliant Pink Iceberg, Brownie, Everest Double Fragrance, Moon Shadow, Bewitched, Pimlico ’81, Amelia Earhart, The Doctor, School Girl, Yellowstone, Octoberfest, Charles Dickens, Dynamite, and Smiles.

Maybe gardening’s not so boring after all.

Huntington Rose Garden on a sunnier day in 2013 (Photo:Tim Jones)
Huntington Rose Garden on a sunnier day in 2013 (Photo:Tim Jones)

Richard Feynman’s Grave

Richard Feynman's Grave at Mountain View Cemetery (Photo:Tim Jones)
Richard Feynman’s Grave at Mountain View Cemetery (Photo:Tim Jones)

Today I paid my respects at the grave of physicist Richard Feynman, interred with his wife Gweneth at the Mountain View Cemetery in Altadena, California.  Feynman died of cancer in 1988 and his wife died the following year.

Richard Feynman's Grave (Photo:Tim Jones)

The grave is marked by a very simple plaque, which my wife and I would never have found without the help of the cemetery staff.  Even then, until we brushed it off, the plaque was barely visible among the leaves and twigs –  fallout from the Santa ana winds that have just ripped through the region.

Richard Feynman at Fermilab. Image in public domain and available via Wikicommons

Today was calm and sunny though, and the cemetery is a beautiful spot to find yourself.  Lots of trees with birds and squirrels running about, the whole overlooked by the San Gabriel Mountains and Mount Wilson (of 100 inch telescope fame).

Feynman researched and taught as Professor of Physics at the nearby California Institute of Technology in Pasadena from 1950 until his death.

Here are some more photos at the cemetery:

If you don’t know about Richard Feynman, I recommend in addition to his Wikipedia  page you check out the biographies Genius by James Gleick, and Quantum Man by Lawrence Krauss.  I also enjoy failing to completely understand (note the word order) Feynman’s 1979 Douglas Robb Memorial Lectures on Quantum Electro-dynamics (QED).

More recently, here’s physicist Leonard Susskind’s personal insight on the man in his January 2011 TED talk ‘My friend Richard Feynman’

and the BBC Horizon ‘No Ordinary Genius’:

Unweaving the Waterfall – Erasmus Darwin at Vauxhall Gardens

Grandson Charles and Grandfather Erasmus Darwin had at least one thing in common besides their illustrious name: they both took delight in figuring out how the world works – which isn’t to say they always followed the same interests.

Charles, we know, focused on the natural world – often in great, great, detail.   Erasmus, less fixated but still very much the naturalist, engaged also with just about every aspect of science, technology and the trials and tribulations of the human condition you can imagine.

Erasmus DarwinCharles Darwin

As happy in the botanical garden as the coachmaker’s yard or canal digger’s trench – it was all the same to him, many are the fields where Erasmus Darwin’s substantive contributions, too often unsung, resonate to the present day.

And while Charles was doubtless adventurous in mind and deed – he did afterall make the voyage of the Beagle – Erasmus, in the broader sense I would argue, ‘got out more’.

No surprise then, one evening in 1756, to find a 24 years young Erasmus Darwin at the epicentre of London society and entertainment: the pleasure gardens at Vauxhall.  Less surprising still to find him back at his Nottingham lodgings pre-occupied with reverse-engineering the Gardens’ then prize crowd-pulling spectacle: the artificial waterfall, or Cascade – more of which later.

Vauxhall Gardens in 1751 (five yrs before Erasmus's visit) Samuel Wale (Wikicommons)

The twelve acre Vauxhall Gardens operated from 1661 to 1859, and enjoyed a fantastically diverse clientele.  Anyone who was anyone – or aspired to be –  had to show their face: from Kings and Queens to honest tradesmen, to a dependable spattering of pick-pockets and prostitutes.

Entertainments at Vauxhall (Photo:Tim Jones. Exhibit at Museum of London)

All mixed shoulder to shoulder, intent on  enjoying music, dancing, or one of the many laid-on spectacles: illuminations, fireworks, circus acts, mechanical wonders, balloon rides, battle recreations and panoramas celebrating the fetes of great explorers.  Top of the list for many would be a romantic diversion with a favoured beau or belle under the tree-covered walkways.

Vauxhall Gardens by David Coke and Alan BorgIncidentally, if you’re wondering what prompted this post – digging around in a pleasure garden – it’s down to my latest reading: a new History of Vauxhall Gardens, by David Coke and Alan Borg1: a beautifully presented, comprehensive, and accessible read.  Check out the book’s website here and write-ups in the Guardian here and here

I’ve suffered from amateur social historian syndrome since arriving in London eleven years ago – it’s hard to avoid when the place drips with the stuff; but the Vauxhall interest is closer to home – literally; my old flat on the Vauxhall Bridge Road overlooked the former Gardens’ site.  Now home to a plain-vanilla grassed park, the only reminder of former glories is the yearly bonfire night sputter of fireworks launched by good-natured, if boisterous, locals. (On which theme, check out this earlier post).

Echo of past glories. View from my flat in 2003: fireworks rising from the former site of Vauxhall Gardens (Photo: Tim Jones)

Reading the new history though, I was intrigued by how few famous scientists (natural philosophers in their day) or technical folk are associated with the Gardens, either as self-reporting visitors or through third-party narratives .

Maybe the great and the good of the scientific establishment eschewed egalitarian Vauxhall in favour of the more exclusive (and expensive) Ranelagh Gardens across the river in Chelsea?  At least there was a stone bust of Isaac Newton on permanent display at Vauxhall.

Anyhow, it’s entirely possible a trawl through the personal letters of individuals, where they’re catalogued, would turn up further references.

For my part, I checked out Erasmus’s letters –  and he didn’t disappoint.

Coming back to the artificial waterfall or cascade for a moment.  Installed in 1752, Coke & Borg say of it:

To add to its theatricality, the Cascade was concealed behind a curtain which was drawn back at a particular time in the evening, as night fell, to reveal a three-dimensional illuminated scene of a landscape with a precipitous waterfall; the illusion was created with sheets of tin fixed to moving belts, turned by a team of Tyer’s [the owner] lamplighters; when it was running, the noise and spectacle must have been terrific 1.

Then I found this letter from Erasmus, dated 9th Septemebr 1756, describing his interpretation of the operation of the spectacle to his friend Albert Reimarus, drawing and all:

Erasmus's drawing of the artifiicial waterfall or cascade at Vauxhall Gardens (Picture credit: The Collected Letters of Erasmus Darwin, Cambridge University Press, 2007, Letter 56-6)

The artificial Water-fall at Vaux Hall I apprehend is done by pieces of Tin, loosely fix’d on the Circumferences of two Wheels.  It was the Motion not being perform’d at Bottom in a parabolic Curve that first made me discover it’s not being natural.  The Velocity at Top is not so great to my rememberance as at the Bottom half of the fall, as I suspect the top Wheel is less than the lower one; a Shade is put where the Wheels join.  At Bottom are many less Wheels I conjecture.  Now the Velocity of the fall from a to b not being encreased was another thing that shock’d my Eye.  What you mean when you say “let the Water fall  over a Parabola etc”, I don’t understand.

Photo:Tim Jones. Exhibit at Museum of London.

I’m taking expressions like “The Velocity at Top is not so great to my remembrance….” as evidence Erasmus actually visited the Gardens himself in the summer of 1756, possibly accompanied by Reimarus.

For Erasmus, the waterfall ‘game’ was given away by the shape of the flow – something other than parabolic, and not moving at the expected relative speeds.

In fairness to the designer (the concept likely derived from Francis Hayman’s theatrical stagecraft), that exposing the spectacle as anything other than natural required such analysis seems high praise indeed!  Incidentally, Coke & Borg maintain no visual representation of the cascade exists, so this might be as close as we get.

(As an aside, there’s also evidence Erasmus’s sister Susannah (Sukey) visited the Gardens.  In a letter of 12th June 1759 to his wife Mary (Polly), Erasmus accuses his sister of exagerating the number of people attending, 30,000, saying that number would not fit3 (although audiences of 12,000 are known to have gathered).  There’s also a much later association with Charles Darwin, that appears in the correspondence4; not that he visited the Gardens but, as a twelve year old boy, having watched one of Vauxhall’s favourite performers, a ventriloquist named Mr Alexandre, did imitations of animal calls – interesting eh?)

We should take care when talking about Erasmus in this period not to visualise him along the lines of the podgy, red-cheeked albeit aimiable 38 year old captured by Joseph Wright and hanging in the National Portrait Gallery.  In 1756, Erasmus was 24 years old, single (he married Mary/Polly Howard the following year), and largely unknown; he’d only two months earlier unpacked his bags in Nottingham to start his first medical practice.

So this is before he moved to Lichfield, and way before the invitation to become the King’s physician, his rivalry with Samuel Johnson (of dictionary fame and a regular at Vauxhall Gardens to the degree he appears in contemporary prints), or his adulation as England’s best loved poet.  Moreover, the brief spell Erasmus spent in Nottingham is sparsley covered in the literature, with no mention in the standard biographies of trips to London or the Gardens. There’s just the one letter as far as I can tell.

In conclusion, it’s nice to see Erasmus’s early credentials as both engineer and bon viveur reinforced in the one story (however much, as a fan, that assessment might be tainted by confirmation bias :-)).

In their longevity, Vauxhall Gardens represent a unique microcosm, a laboratory for the study of change in societal norms, fashion, culture, politics and contemporary opinion.  Coke’s and Borg’s analysis refreshes our insight on these, and placing Erasmus Darwin at the scene adds to our understanding of his early life.

Update 4/9/11

Twitter friends have suggested Samuel Pepys as an example of a ‘scientist’ known to have visited Vauxhall.  He for sure counts as one of the establishment great and the good, and was a president of the Royal Society to boot.  Coke and Borg do talk about Pepys, who wrote at some length about Vauxhall Gardens in his famous diaries.  I’m afraid I associate Pepys so strongly with the Gardens, and for all his other interests and achievements – not just in science, that I completely forgot to mention him – poor chap.  Still, he’s one guy, and it would be interesting to see if any of the other famous scientific names of the day including Newton, Wren, or, as Rebekah Higgitt (@beckyfh) suggested via twitter, Edmund Halley or Joseph Banks made mention of Vauxhall experiences in their letters.  I must say, if I had my bust up there in all its glory like Newton did, I’d be checking up on it every friday night.

Of related interest on Zoonomian: The Other Darwin Genius



1) Vauxhall Gardens A History, Coke, David., Borg, Alan., Yale, 2011

2) King-Hele, Desmond (Ed.), The Collected Letters of Erasmus Darwin, Cambridge, 2007, [56-6] p.35

3) King-Hele, Desmond (Ed.), The Collected Letters of Erasmus Darwin, Cambridge, 2007, [59-1] p.47

4) Darwin Correspondence Database, accessed on Thu Sep 01 2011 15:56:18 GMT+0100 (BST)


Other Sources

King-Hele, Desmond, Erasmus Darwin 1731-1802, Macmillan, 1963

King-Hele, Desmond, The Essential Writings of Erasmus Darwin, MacGibbon & Kee, 1968

King-Hele, Desmond, Erasmus Darwin A Life of Unequalled Achievement, Giles de la Mare, 1999


Book Review: The Sky’s Dark Labyrinth, by Stuart Clark

Hardcover: 272 pages

  • Publisher: Polygon (1 May 2011)
  • Language English
  • ISBN-10: 1846971748
  • ISBN-13: 978-1846971747
  • Product Dimensions: 20.6 x 15.4 x 3 cm





Galileo Galilei’s scrape with the Roman Catholic Church is well known.

His suggestion that the Earth spins on its axis and orbits around the Sun was an afront to scripture that got him branded as a heretic and almost burnt at the stake. How he first became aware of the full peril of his situation is less well known: on a rooftop in Rome, eavesdropping whilst taking a pee behind a bush.

Maybe that’s how it happened, maybe not – either way, the Earth won’t stop turning.

But it’s through these touches of imaginative license: sometimes humorous, sometimes tragic, on occasion disturbingly vivid, that Stuart Clark breathes life into the characters of his first novel, The Sky’s Dark Labyrinth.

The title comes from an episode in the book, where Galileo explains the hopelessness of trying to understand the universe without the correct language – mathematics; to do so is to “wander about lost in the dark labyrinth of the sky.”  But don’t panic, it’s an equationless drama.

In this first part of a trilogy that reaches from the sixteenth to the twentieth century, we follow the lives of the astronomers Tycho Brahe (1546-1601), Johannes Kepler (1571-1630) and Galileo Galilei (1564-1642) as they challenge the religiously inspired orthodoxy of the times: an Earth-centered universe with the Sun and planets orbiting around in perfect circles – just as God intended.

Each astronomer has special skills and his own ideas about the cosmos:

Tycho, the meticulous naked-eye observer, happy for the Sun to orbit the Earth, yet convinced the other planets revolve around the Sun.

Galileo, arguably the father of evidence-based thinking, points his telescope skyward to see mountains on the moon, satellites around Jupiter, moon-like phases on Venus and Mercury, and spots on the Sun (Clark reminds us Galileo didn’t actually invent the telescope) – each observation a blow to the accepted model of the universe and Aristotle’s concept of a perfect heaven.

And Kepler, obsessed with geometry, turns a rigorous mathematical eye to his compatriots’ data to derive a model of eliptical planetary motion that, relativistic effects aside, is valid to this day.

On the journey, we share starry rooftop nights with Tycho and his armillary spheres and sextants; and with Galileo and his telescope. We encounter scientific concepts, painlessly embedded in the story, from stellar parallax to Kepler’s defining relationship for a planet’s distance and period round the Sun. 

We meet the landmark publications that captured these ideas: Kepler’s discussion of perfect polygons Mysterium cosmographicum, his treatise on Mars: the Astronomia nova, and the Rudolphine Tables of star positions; Galileo’s telescope observations in Sidereus Nuncius and his more troublesome endorsement of Copernican ideas in Dialogue Concerning the Two Chief World Systems.

The whole is delivered through a pacey narrative that switches back and forth through time and space.  One moment we’re in Rome, then Prague, then Florence, then Rome again.  Thus Clark weaves his factually-based interplay of lives and ideas.

As in any drama, characters are developed in contexts that resonate with our personal experience: relationships, families, squabbles, births, marriages and deaths – as far as that’s possible 400 years on.   Is that illusory?  Can we ever really see from behind 16th century eyes?   No, we can’t.  But how else to share Kepler’s wonder as he steps out onto the observatory roof, or taste Tycho’s not-so-scientific bon vivre lifestyle and lordly pride, or feel Galileo’s chill dread as he anticipates what a rabid Inquisition has in store?

And that, in a nutshell, is Clark’s proposition.

It’s one where he’s shown due respect for the underlying history, reflected perhaps in a favouring of credible human vignettes over elaborate manufactured sub-plots.  So, lots of expansion on the meetings, schemes, and conflicts that must have taken place but would never be recorded – scenes that  can be directed and embellished to divert and entertain without compromising the main account.

In this regard, it’s a very different book to, say, Edward Rutherfurd’s London, where the main story lines are totally fictional.  Clark’s work comes over as based on historical record and scientific fact.  It’s important, as historians of science in particular can, understandably, take issue with inaccurate or controversial portrayals; I’m thinking of a recent defence of Nevil Maskelyne, the 18th century Astronomer Royal, demonised in the film version of Dava Sobel’s Longitude.

The Sky’s Dark Labyrinth begins in Rome, where a defiant Giordano Bruno, comfortable only with his conscience, waits in a cell to be burnt at the stake for heresy.

Johannes Kepler, an outcast Lutheran, arrives in Bohemian Prague to join the service of Tycho Brahe, and get a first sniff of the observational data he’ll one day build into a planetary model.  He also hears about one Galileo Galilei of Padua, and the wonderful discoveries he’s made with his telescope (before long Kepler will have one of his own).

And all the time the Roman Catholic Church is watching, keeping tabs on these dangerous individuals, their troubling independence and inconvenient appeal to evidence.   Kepler is spyed on – his mail intercepted. Galileo, at first encouraged by the Pope, is told in no uncertain terms to leave theological interpretation to the Church; but his thoughts are already committed to print. Thus the slippery slide to persecution, recantation, and repression is joined.

The plot moves between the bloody war-torn streets of Prague and the red robed intrigue of Vatican corridors.  Current events in Reformation Europe are dominated by the struggle between an increasingly Jesuit-influenced Catholic Church and a rising tide of Lutherism.  And our astronomers are in the thick of it.

Far from being godless atheists, they aim to explain God’s works – not undo them.  Yet a Catholic Galileo and a Lutheran Kepler still each grapple to rationalise their ideas to themselves and to a world of dogmatic orthodoxy.  A world where political, theological, and philosophical considerations hold sway over rationalism; where solidarity of belief and allegiance to the group is prized over individual will, conscience, or even physical proof; where mathematical descriptions are acceptable as professional tricks, but will never define truth; where witchcraft is a burning issue, and astronomy is inseparably tied up with the superstition of astrology.

Indeed, Kepler makes a good living drawing up horoscopes for wealthy patrons and courtly sponsors – a trade he revisits as the need arises (Clark actually credit’s him with a rather modern pragmatism on these issues).

Reformation Europe is also a great background for some of Clark’s more vivid visualisations, reminiscent of a Terry Gilliam movie in their medievalism.   I love the “gobs of some thick unguent” Kepler spies clinging at the margins of Tycho’s prosthetic nose when they first meet, and the mood-setting ‘unpleasant tang of tallow’ in Kepler’s study.

Life is dirty, smelly, and not a little dangerous.

On the downside, I occasionally lose track in the switching interplay of events and locations, feeling the need to draw little timeline diagrams – lest I get totally lost in the labyrinth.  And oblivious to any description or other literary signposting, I only ever thought of our heros as bearded old men.  I’ll call it William Shakespeare syndrome- there just aren’t enough ‘before they were famous’ portraits out there.

But none of that detracted from The Sky’s Dark Labyrinth as a thoroughly entertaining and recommended read.

In capturing that essential excitement of the night sky, unchanged over the centuries, Clark has created a work accessible to all comers, and one that astronomers and history fans in particular will doubtless lap up.

I look forward to meeting Isaac Newton, Albert Einstein and Edwin Hubble in future installments.

Stuart Clark’s website is at




Thomas Huxley’s Birthday Timeline

Thomas Huxley
I’ve just started playing with Dipity timelines, and as it’s Thomas ‘Darwin’s Bulldog’ Huxley’s birthday today, 4th May, here’s a work-in-progress showing some of the events in his life.

I’ll build in more links and events as I go along. For now here’s Happy Birthday Thomas Henry Huxley (1825-1895).

Photo: Tks S.Klinge