Tag Archive: science

May 19 2018

Book review: The Anatomy of Colour by Patrick Baty

anatomy_of_colourThe Anatomy of Colour by Patrick Baty is a history of painting as decoration for houses and buildings stretching back 350 years or so. The Painter’s Company dates all the way back to 1283, and the practice of decorative house painting back into antiquity. There is direct evidence for this preserved in Pompeii.

As I recall I’ve been following Patrick on social media for quite some time, in part because what he does relates to my former professional interests. Anatomy picks up on work I used to do in colour measurement. I did it in a different context – for a “fast moving consumer goods” company making washing liquid, shampoo and the like. It also has some relevance to work I do now on dating buildings.

At the beginning of the book the materials used to generate colours and paints are discussed. Typically these are minerals or plant materials, synthetic colourants only started to become available in the 19th century. Lead carbonate (white lead) was long used as the basis for many oil paints (of all colours), despite it’s known toxicity. It was replaced by zinc oxide in the later 19th century and now titanium dioxide is used. Confusingly from the early period “pink” used to mean a yellowish colour derived from plant material. Also mentioned are the linseed oil that formed the carrier for most paints well into the 20th century.

Following this introduction a number of broad themes are discussed in successive periods so for example in each period we learn about the favoured colours and colour schemes, colour theories and systems, and the key books relating to decorating and colour. Technology is a slowly changing background to this. In the beginning painters bought the pigments and oils and made their own paint, possible making pigments from raw materials. Pigment pastes in metal tubes came into use in the 19th century with tinned paints a 20th century innovation, as far as I can tell.

I’ve always had a problem with distemper, a suspension of chalk in a glue base which can be washed off and reapplied, mainly because I learnt about distemper, the disease of dogs first! Distemper was used as a disposable wall covering until the late 19th century when it started to be replaced by other commercial formulations until they were in turn replaced with emulsion paints sometime after the Second World War.

Something I hadn’t considered before was the importance of colour in horticulture and zoology. Darwin took a book on colour on his trip around the world. He needed it to describe the colours of animals and plants as they were collected since there was no photography and specimen preservation techniques would not necessarily preserve colour. More recently colour systems have been developed around the needs of horticultural. The red of a robins breast is probably as good a reference to a colour as could be obtained artificially until into the 20th century. Similar the yellow of a daffodil.

The colour systems discussed are a little different from those I used in scientific colour measurement, the closest approach is the Munsell “hue, saturation, value” system. In general the systems presented here are focused around defining words to describe colours to aid communication and specification, and establishing harmonious colour combinations. My work was more involved in measuring colour in a machine to see the effect of different washing liquid formulations, or similar.

In the 20th century Britain saw standardisation of colours with recommendations for the painting of commercial and public buildings. The post-war rise in DIY is well-known but housepainting was seen as something a gentleman might undertake even in the 18th and 19th century.

Early on in the book Baty shows some paint cross-sections which are discussed very briefly. I must admit I find this forensic side very interesting and I was a bit disappointed that there was not more of this – I can see how it doesn’t fit with the main audience for the book. I found the chapter / section numbering a bit confusing, there are two levels in the hierarchy and both use Roman numerals!

The book is beautifully illustrated with colour reproductions of many of the different colour systems used over the years, as well as photographs of interiors following the styles discussed. For practioners in the investigation (and recreation) of decorative schemes I can see this book being absolutely essentially, and as a more casual reader I enjoyed it too.

May 13 2018

Book review: Other minds by Peter Godfrey-Smith

other_mindsOther Minds by Peter Godfrey-Smith is about consciousness through the lens of cephalopods, a group comprising octopuses, cuttlefish, squid and the nautiluses.

Godfrey-Smith is a philosopher, rather than a scientist. This reflects the theme of the book, Godfrey-Smith’s idea is to understand our consciousness by looking at a creature with as radically different a consciousness as he can find. So his book is more a philosophical rather than a scientific view on consciousness which to my mind is no bad thing.

I was particularly impressed by Charles the octopus, one of three which experimenters used to try to measure octopus intelligence. The other two octopuses in their study put in some effort to carry out the tests presented whilst Charles insisted on squirting water at the experimenters and being otherwise uncooperative. It does make you wonder whether measures of animal intelligence are more a combination of willingness and intelligence. Perhaps the smarter animals just can’t be doing with intelligence tests. Squirting water at lights in aquariums to put them out seems, apocryphally, to be quite common behaviour amongst octopuses.

Mrs H is undertaking a doctorate in education and it strikes me that her mode of doing research, qualitative with relatively few subjects has more in common with this type of study than the experimenters care to admit. In this type of experiment the narrative rather than the result may be more important. So measuring the intelligence of the octopuses, or the time it took them to complete a learning task, is less important than the narrative of how they performed in the experiment.

The book weaves together cephalopod biology with Godfrey-Smiths own observations of cephalopods in the wild. I was intrigued to learn that the octopus brain is wrapped around the digestive tract which has been observed to lead to problems when attempting to eat particularly spikey foods. More generally, the neural material of an octopus is not all to be found in the “brain” it is distributed around the body. Octopus legs appear to have a degree of autonomy in at least deciding how to achieve a goal, even if the “brain” decides what the end goal might be.

Cuttlefish and octopuses have amazing abilities to change their appearance both in terms of colour, but also physical texture – they can make themselves bumpy. Interestingly, as far as we can tell they are unable to see the colours they produce – the photoreceptors in their eyes are of a single type. However, there is clearly something else going on – photoreceptors are found throughout the body of the cephalopod, and they are able to match background colours exquisitely. Furthermore, with the chromatophore and other colour producing structures also present a different mechanism for producing colour sensitivity is quite feasible – for example using those chromatophores as a filter “wheel” that sits in front of the light sensitive cells.

Godrey-Smith highlights that, although the cephalopods have a huge ability to make signals, because they are not a social species their ability to use those signals is limited. This is contrast to species such as baboons who have a more limited ability to generate vocal signals but, as a social species, have a much greater ability to interpret those signals in terms of establishing their position in a hierarchy and understanding how the hierarchy has changed.

Close to the end of the book, there is a terrible denouement: the typical cephalopod lifespan is only a couple of years. These creatures, so full of potential, are but brief inhabitants of the earth. Godfrey-Smith draws parallels with the Replicants in Bladerunner here. Their brief lives are understood in terms of their dangerous environment which has led to an evolutionary strategy of large broods of young, easily lost.

The book finishes with a discussion of “Octopolis” a location in Australia where octopuses, unusually, congregate and where Godfrey-Smith did a large part of his observations discussed throughout the book. Also we find here that he is involved in scientific publication.

Overall, one is left with the feeling of cephalopods having been an opportunity missed in the consciousness stakes. They have all the mental machinery but their truncated lives and limited social behaviour means that in all likelihood the opportunity is unfulfilled. This is a consciousness-centric human view, no species is striving for consciousness or intelligence they are doing what is needed for there species to continue in the niches they find themselves.

May 26 2016

Book review: Lab Girl by Hope Jahren

labgirlLab Girl by Hope Jahren is an unusual book. It’s an autobiography which mixes in a fair amount of plant science. It is beautiful to read. It is strong on what being a scientist means. The closest comparison I can think of are Richard Feymann’s “Surely you are joking, Mr Feynmann” memoirs which are rather more anecdotal.

Lab Girl is chronological, starting from Jahren’s early memories of visiting the lab in her father’s school after hours but then fast forwarding to her academic career setting up laboratories in Georgia, Baltimore and finally Hawaii. It isn’t encyclopaedic in providing a detailed record of Jahren’s personal and scientific life.

A thread through the whole book is Bill, her trusty research assistant. Bill starts as a keen undergraduate who Jahren takes on when she gets her first academic position. I think in some ways Bill is something of a product of the US academic system, with support staff often funded on short term grants. In the UK such people tend to be employed on a permanent basis by the institution. My Bill was Tom when I was a PhD student, Pete and Roger when I was an assistant director of research. As a lecturer I didn’t have a Bill, and maybe that was my problem.

Several themes intertwine through the book. There is the day to day activity of a lab: labelling things, repetitive sample preparation, measuring things, fighting with equipment to get it to measure things. Wrangling undergraduates and postgraduates. There are trips out into the field. For Jahren, as a biologist, the field is very literally the field (or Irish bog, Canadian tundra etc). There is attending academic conferences. Mixed with this there is the continual struggle for tenure and funding for your research and the fight for resources with grants that don’t go quite far enough.

It’s fair to say Jahren put in an awful lot more hours than I did as a young academic but then I didn’t turn into an successful, older academic. Make of that what you will. It’s difficult to measure your success as an academic, grant applications are so hit and miss that winning them is only a measure of your luck and skill at writing grant applications, papers are relatively sparse and rarely provide much feedback. Sometimes putting in hours seems the only way of measuring your worth.

A second strand is plant biology, mingling basic background and the cutting edge research that Jahren does. I absorbed this in ambient fashion, I now think a little more like a tree. I didn’t realise that willow deliberately drop  whole branches so as to propagate themselves. This explains the success of our willow dome construction which was made by unceremoniously plonking willow sticks into the ground and weaving them together. They then gamely got on and grew. Soil is a recurring theme in the book, the teaching of the taxonomy of soil to undergraduates in particular. I had glimpses of this rich topic whilst doing a Kaggle challenge on tree cover. Finally, there is mass spectroscopy and isotope analysis.

And finally there is the personal, Jahren’s mental health, her struggles with pregnancy, marriage and a growing son. Some of this is painful and personal reading but its good to hear someone saying what we perhaps find unsayable. Lab Girl says relatively little about the difficulties she particularly faced as a woman, although Jahren has written about it elsewhere.

I observed a while back when reviewing In Defence of History that whilst historians seemed interested in literary style in technical writing, scientists rarely did. Lab Girl is an exception, which makes it well worth a read.

At the end of the book, Jahren asks us all to plant a tree. I pleased to say we’ve achieved this, although perhaps not quite the right sort of trees for American sensibilities, used to larger gardens. In the front garden we have a crab apple tree which, in the right sort of year, flowers on my birthday. There are several apple trees spread through the front garden. In both front and back gardens we have acers and now, at the bottom of the garden we have an amelanchier. I have longed for a Cedar of Lebanon in my front garden but fear I will never own a house large enough for this to be practicable.

Oct 14 2012

Book Review: Alan Turing: The Enigma by Andrew Hodges

2012editionA brief panic over running out of things to read led me to poll my twitter followers for suggestions, Andrew Hodges’ biography of Alan Turing, Alan Turing: The Enigma  was one result of that poll. Turing is most famous for his cryptanalysis work at Bletchley Park during the Second World War. He was born 23rd June 1912, so this is his 100th anniversary year. He was the child of families in the Indian Civil Service, with a baronetcy in another branch of the family.

The attitude of his public school, Sherbourne, was very much classics first, this attitude seems to have been common and perhaps persists today. Turing was something of an erratic student, outstanding in the things that interested him (although not necessarily at all tidy) and very poor in those things that did not interest him.

After Sherbourne he went to King’s College, Cambridge University on a scholarship for which he had made several attempts (one for my old college, Pembroke). The value of the scholarship, £80 per annum, is quite striking: it is double the value of unemployment benefit and half that of a skilled worker. He started study in 1931, on the mathematics Tripos. His scholarship examination performance was not outstanding. Significant at this time is the death of his close school friend, Christopher Morcom in 1930.

King’s is a notorious hotbed of radicals, and at this time Communism was somewhat in vogue, a likely stimulus for this was the Great Depression: capitalism was seen to be failing and Communism offered, at the time, an attractive alternative. Turing does not appear to have been particularly politically active though.

During his undergraduate degree, in 1933, he provided a proof of the Central Limit Theorem – it turns out a proof had already been made but this was his first significant work. He then went on to answer Hilbert’s Entscheidungsproblem (German for “Decision Problem) in mathematics with his paper, “On computable numbers”1. This is the work in which he introduced the idea of a universal machine that could read symbols from a tape, adjust its internal state on the basis of those symbols and write symbols on the tape. The revelation for me in this work was that mathematicians of Turing’s era were considering numbers and the operations on numbers to have equivalent status. It opens the floodgates for a digital computer of the modern design: data and instructions that act on data are simply bits in memory there is nothing special about either of them. In the period towards the Second World War a variety of specialised electromechanical computing devices were built, analogue hardware which attacked just one problem. Turing’s universal machine, whilst proving that it could not solve every problem, highlighted the fact that an awful lot of problems could be solved with a general computing machine – to switch to a different problem, simply change the program.

Alonzo Church, at Princeton University, produced an answer for the Entscheidungsproblem  at the same time; Turing went to Princeton to study for his doctorate with Church as his supervisor.

Turing had been involved in a minor way in codebreaking before the outbreak of World War II and he was assigned to Bletchley Park immediately war started. His work on the “Turing machine” provides a clear background for attacking German codes based on the Enigma machine. This is not the place to relate in detail the work at Bletchley: Turing’s part in it was as something of a mathematical guru but also someone interested in producing practical solutions to problems. The triumph of Bletchley was not the breaking of individual messages but the systematic breaking of German systems of communication. Frequently, it was the breaking of a system which was critical in principle the Enigma machine (or variants of it) could offer practically unbreakable codes but in practice the way it was used offered a way in. Towards the end of the war Turing was no longer needed at Bletchley and he moved to a neighbouring establishment, Hanslope Park where he built a speech encrypting system, Delilah with Don Bayley – again a very practical activity.

Following the war Turing was seconded to the National Physical Laboratory where it was intended he would help build ACE (a general purpose computer), however this was not to be – in contrast to work during the war building ACE was a slow frustrating process and ultimately he left for Manchester University who were building their own computer. Again Turing shows a high degree of practicality: he worked out that an alcohol water mixture close to the composition of gin would be almost as good as mercury for delay line memory*. Philosophically Turing’s vision for ACE was different from the American vision for electronic computing led by Von Neumann: Turing sought the simplest possible computing machinery, relying on programming to carry out complex tasks – the American vision tended towards more complex hardware. Turing was thinking about software, a frustrating process in the absence of any but the most limited working hardware and also thinking more broadly about machine intelligence.

It was after the war that Turing also became interested in morphogenesis2 – how complex forms emerge from undifferentiated blobs in the natural world, based on the kinetics of chemical reactions. He used the early Manchester computer to carry out simulations in this area. This work harks back to some practical calculations on chemical kinetics which he did before going to university.

Turing’s suicide comes rather abruptly towards the end of the book. Turing had been convicted of indecency in 1952, and had undergone hormone therapy as an alternative to prison to “correct” his homosexuality. This treatment had ended a year before his suicide in 1954. By this time the UK government had tacitly moved to a position where no homosexual could work in sensitive government areas such as GCHQ. However, there is no direct evidence that this was putting pressure on Turing personally. Reading the book there is no sick feeling of inevitability as Turing approaches the end you know he has.

Currently there are calls for Turing to be formally pardoned for his 1952 indecency conviction, personally I’m ambivalent about this – a personal pardon for Turing is irrelevant: legal sanctions against homosexual men, in particular, were widespread at the time. An individual pardon for Turing seems to say, “all those other convictions were fine, but Turing did great things so should be pardoned”. Arnold Murray, the man with whom Turing was convicted was nineteen at the time, an age at which their activities were illegal in the UK until 2000.

What struck me most about Turing from this book was his willingness to engage with practical, engineering solutions to the results his mathematical studies produced.

Hodges’ book is excellent: it’s thorough, demonstrates deep knowledge of the areas in which Turing worked and draws on personal interviews with many of the people Turing worked with.


1. “On computable numbers, with an application to the Entscheidungsproblem”, A.M. Turing, Proceedings of the London Mathematical Society 42:230-265 (1936).

2. “The Chemical Basis of Morphogenesis”, A.M. Turing, Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, Vol. 237, No. 641. (Aug. 14, 1952), pp. 37-72.

3. My Evernotes for the book

4. Andrew Hodges’ website to accompany the book (link)

Jun 22 2012

Book Review: Huygens–The Man Behind the Principle by C.D. Andriesse

huygens-man-behind-principle-c-d-andriesseThis post is a review of C.D. Andriesse’s biography “Huygens: The Man Behind the Principle”. Huygens Principle concerns the propagation of light but he carried out a wide range of research, including work on clocks, Saturn (discovering its moon “Titan” and hypothesizing the existence of its rings), buoyancy, circular motion, collisions, musical scales and pendulums. Huygens has made passing appearances in my blog posts on the French Académie des Sciences, on telescopes and also on clocks.

On the face of it is surprising that he is not better known, looking around for biographies of him one finds a rather short list. Andriesse puts this down to much of the personal documentation being in Dutch. The scientist in me feels there should be some quantitative way of measuring how “well known” a historical figure is now, and how “important” they were – I suspect this is an impossible programme. On completing the book I suspect a couple of factors play a part here: Huygens represents something of a transitional figure between the work of Galileo/Descartes, and Newton/Leibniz. Similarly his practical work on clocks and telescopes was impressive for its time but superseded not long thereafter. What we do now in physics owes much more to Newton than to Galileo, furthermore Newton although not prolific published more promptly than Huygens and was President of the Royal Society for 20 or so years before his death in post, whilst Huygens left L’Académie des Sciences sometime before his death in not particularly auspicious circumstances. It isn’t entirely clear whilst reading the book, but it becomes obvious that frequently Huygens’ work was done over long periods and only published quite a long time after it was started, often posthumously.

Huygens was born in the Hague in 1629 and died 1695. Christiaan Huygens’ father, Constantijn was a senior Dutch diplomat and a regular correspondent with René Descartes. Constantijn also met Francis Bacon (and was clearly impressed by him), Bacon and Descartes were important in shaping the development of science in the early 17th century. Bacon in particular set the scene for the way of doing science both in the Royal Society and  L’Académie des Sciences. Constantijn set his son off on a regime of study in the classics, with a view to him becoming a lawyer and following in his footsteps as a diplomat. Sometime around 1643, when Christiaan was 14 years old he started to show promise in mathematics.

Huygens senior provided introductions to Marin Mersenne who introduced him to those circles who became the Académie des Sciences in France. Christiaan Huygens was a paid director of science at L’Académie from its foundation in 1666 until he was excluded from it shortly after the death of Jean-Baptiste Colbert, founder of the organisation and his principle patron, in 1683. The exclusion arose from a combination of the loss of this patron, religious differences, absence due to illness, personal vendettas, opposition to membership of any foreigner and his demand for higher remuneration. Aside from this period at L’Académie, Huygens appears to have lived on the wealth and position of his father.

There’s no doubt that he made significant contributions in the area of mechanics, going beyond what Galileo and Descartes had done but his work was superseded almost immediately by that of Newton, and Leibniz, particularly in the methods of calculus which they developed. Calculus is a tool which makes much of the complex geometrical work that Huygens did obsolete. Leibniz was an informal pupil of Huygens, and they kept up a lengthy correspondence. He also had some exposure to Isaac Newton via the Royal Society.

Andriesse claims that Huygens wrote the first physics formula, relating to collisions. I think we should probably take this with a pinch of salt, but looking at the work he did do on circular motion, collisions, buoyancy, the motion of the pendulum and the shape of a catenary as well as his work on optics it is all very familiar to those that studied physics (at least to the age of 18).

Alongside his mathematical and theoretical physics work, Huygens also made contributions to the development of both clocks and telescopes. He introduced the pendulum clock, and a design of his was tested for determining the longitude by the Dutch East India Company. In practical terms this was not successful but it was a valiant first try. He also made lenses and constructed his own telescopes, here he appears to have been a competent technician and an able theoretician but not reaching the level of Newton, who constructed his own reflecting telescope – the first practical example of its type which was not exceeded for some 30 years or so.

This is a detailed biography of Huygens, drawing heavily on his personal correspondence and covering his scientific achievements in some depth, in the manner of Abraham Pais biography of Einstein. Although the book is pretty readable, the style is odd in places – Huygens is referred to frequently as “”Titan” without any real explanation as to why – it may be that in the original Dutch version, entitled “Titan kan niet slapen” (“Titan can not sleep”) this is a bit more obvious. The author also throws in the odd “Iris” when referring obliquely to sex (at least I think that’s what he’s doing!). Occasionally bits of information are scattered through the text, so we learn when Huygens is born and only 10 pages later do we learn where. There is no strong distinction of when Huygens started working on a publication and when it was actually published.

Perhaps more seriously Andriesse makes an attempt at Freudian analysis of some of Huygens illness, I’m no expert in this but I suspect this approach would be considered out-dated these days. It is also here that the translation perhaps wobbles a bit, with Huygens described as having “symptoms of the hypochondriac” which I think may be a mistranslation of melancholia hypochondriaca which I believe refers more generally to mental illness than the specific modern “hypochondria”.

This said, Andriesse’s biography of Huygens is well worth reading. Christiaan Huygens himself is an interesting subject who made important scientific discoveries across a range of areas.


My Evernotes for the book are here.

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