Oct 23 2014

Book review: Pompeii by Mary Beard

For a change I have been reading about Roman history, in the form of Pompeii: The Life of a Roman Town by Mary Beard.

Mary Beard is a Cambridge classicist. I think it helps having seen her on TV, jabbing her figure at a piece of Roman graffiti, explaining what it meant and why it was important with obvious enthusiasm. For me it gave the book a personality.

I imagine I am not unusual in gaining my knowledge of Roman culture via some poorly remembered caricature presented in pre-16 history classes at school and films including the Life of Brian, Gladiator and Up Pompeii.

Pompeii is an ancient Italian town which was covered in a 4-6 metre blanket of ash by an eruption of nearby Vesuvius in 79 AD. Beneath the ash the town was relatively undamaged. It was rediscovered in 1599 but excavations only started in the mid 18th century. These revealed a very well-preserved town including much structure, artwork and the remains of the residents. The bodies of the fallen left voids in the ash which were reconstructed by filling them with plaster.

The book starts with a salutatory reminder that Pompeii wasn’t a town frozen in normal times but one in extremis as it succumbed to a volcanic eruption. We can’t assume that the groups of bodies found or the placement of artefacts represent how they might have been found in normal daily life.

There are chapters on the history of the city, the streets, homes, painting, occupations, administration, various bodily pleasures (food, wine, sex and bathing), entertainment (theatre and gladiators) and temples.

I’ve tended to think of the Roman’s as a homogeneous blob who occupied a chunk of time and space. But this isn’t the case, the pre-Roman history of the town features writing in the Oscan language. The Greek writer Strabo, working in the first century BC wrote about a sequence of inhabitants: Oscans, Etruscans, Pelasgians and then Samnites – who also spoke Oscan.

Much of what we know of Pompeii seems to stem from the graffiti found all about the remains. It would be nice to learn a bit more about this evidence since it seems important, and clearly something different is going on from what we find in modern homes and cities. If I look around homes I know today then none feature graffiti, granted there is much writing on paper but not on the walls.

From the depths of my memory I recall the naming of various rooms in the Roman bath house but it turns out these names may not have been in common usage amongst the Romans. Furthermore, the regimented progression from hottest to coldest bath may also be somewhat fanciful. Something I also didn’t appreciate was that the meanings of some words in ancient Latin are not known, or are uncertain. It’s obvious in retrospect that this might be the case but caveats on such things are rarely heard.

Beard emphasises that there has been a degree of “over-assumption” in the characterisation of the various buildings in Pompeii. For instance on some reckonings there are huge numbers of bars and brothels. So for instance, anything with a counter and some storage jars gets labelled a bar. Anything with phallic imagery gets labelled a brothel, the Pompeiian’s were very fond of phallic imagery. A more conservative treatment brings these numbers down enormously.

I am still mystified by the garum, the fermented fish sauce apparently loved by many, it features moderately in the book since the house of a local manufacturer is one of the better preserved ones, and one which features very explicit links to his trade. It sounds absolutely repulsive.

The degree of preservation in Pompeii is impressive, the scene that struck me most vividly was in The House of Painters at Work. In this case the modern label for the house describes exactly what was going on, other houses are labelled with the names of dignitaries present when a house was uncovered, or after key objects found in the house. It is not known what the inhabitants called the houses, or even the streets. Deliveries seemed to go by proximity to prominent buildings.

I enjoyed Pompeii, the style is readable and it goes to some trouble to explain the uncertainty and subtlety in interpreting ancient remains.

Once again I regret buying a non-fiction book in ebook form, the book has many illustrations including a set of colour plates and I still find it clumsy looking at them in more detail or flicking backwards and forwards in an ereader.

Sep 21 2014

Book review: Falling Upwards by Richard Holmes

fallingupwardsI read Richard Holmes book The Age of Wonder some time ago, in it he made a brief mention of balloons in the 18th century. It pricked my curiosity, so when I saw his book Falling Upwards, all about balloons, I picked it up.

The chapters of Falling Upwards cover a series of key points in the development of ballooning, typically hydrogen balloons from the last couple of decades of the 18th century to the early years of the 20th century. One of the early stories is a flight from my own home city, Chester. Thomas Baldwin recorded his flight in Airopaidia: Containing the Narrative of a Balloon Excursion from Chester, the eighth of September, 1785. The book does not have the air of a rigorous history of ballooning, it introduces technical aspects but not systematically. It is impressionistic to a degree, and as a result a rather pleasant read. For Holmes the artistic and social impact of balloons are as important as the technical.

In the beginning there was some confusion as to the purposes to which a balloon might be put, early suggestions included an aid to fast messengers who would stay on the ground to provide but use a small balloon to give them “10 league boots”, there were similar suggestions for helping heavy goods vehicles.

In practice for much of the period covered balloons were used mainly for entertainment – both for pleasure trips but also aerial displays involving acrobatics and fireworks. Balloons were also used for military surveillance.  Holmes provides chapters on their use in the American Civil War by the Union side (and very marginally by the Confederates). And in the Franco-Prussian war they were used to break the Prussian siege of Paris (or at least bend it). The impression gained though is that they were something like novelty items for surveillance. By the time of the American Civil War in the 1860’s it wasn’t routine or obvious that one must use balloon surveillance, it wasn’t a well established technique. This was likely a limitation of both the balloons themselves and the infrastructure required to get them in the air.

Balloons gave little real utility themselves, except in exceptional circumstances, but they made a link to heavier-than-air flight. They took man into the air, and showed the possibilities but for practical purposes generally didn’t deliver – largely due to their unpredictability. To a large extent you have little control of where you will land in a balloon once you have gone up. Note, for example, that balloons were used to break the Prussian siege of Paris in the outbound direction only. A city the size of Paris is too small a target to hit, even for highly motivated fliers.

Nadar (pseudonym of Gaspard-Félix Tournachon), who lived in Paris, was one of the big promoters of just about anything. He fought a copyright battle with his brother over his, adopted, signature. Ballooning was one of his passions, he inspired Jules Verne to starting writing science fiction. His balloon, Le Géant, launched in 1863 was something of a culmination in ballooning – it was enormous – 60 metres high but served little purpose other than to highlight the limitations of the form – as was Nadar’s intent.

From a scientific point of view Falling Upwards covers James Glaisher and Henry Coxwell’s flights in the mid-nineteenth century. I was impressed by Glaisher’s perseverance in taking manual observations at a rate of one every 9 seconds throughout a 90 minute flight. Glaisher had been appointed by the British Association for the Advancement of Science to do his work, he was Superintendent for Meteorology and Magnetism at the Royal Greenwich Observatory. With his pilot Henry Coxwell he made a record-breaking ascent to approximately 8,800 meters in 1862, a flight they were rather lucky to survive. Later in the 19th century other scientists were to start to identify the layers in the atmosphere. Discovering that it is only a thin shell – 5 miles or so thick which is suitable for life.

The final chapter is on the Salomon Andrée’s attempt to reach the North Pole by balloon, as with so many polar stories it ends in cold, lonely, perhaps avoidable death for Andrée and his two colleagues. Their story was discovered when the photos and journals were recovered from White Island in the Artic Circle, some 30 years after they died.

Falling Upwards is a rather conversational history. Once again I’m struck by the long periods for technology to reach fruition. It’s true that from a technology point of view that heavier-than-air flight is very different from ballooning. But it’s difficult to imagine doing the former without the later.

Sep 18 2014

Of Matlab and Python

I’ve been a scientist and data analyst for nearly 25 years. Originally as an academic physicist, then as a research scientist in a large fast moving consumer goods company and now at a small technology company in Liverpool. In common to many scientists of my age I came to programming in the early eighties when a whole variety of home computers briefly flourished. My first formal training in programming was FORTRAN after which I have made my own way.

I came to Matlab in the late nineties, frustrated by the complexities of producing a smooth workflow with FORTRAN involving interaction, analysis and graphical output.

Matlab is widely used in academic circles and a number of industries because it provides a great deal of analytical power in a user-friendly environment. Its notation for handling matrix (array) calculations is slick. Its functionality is extended by a range of toolboxes, and there is a community of scientists sharing new functionality. It shares this feature set with systems such as IDL and PV-WAVE.

However, there are a number of issues with Matlab:

  • as a programming language it has the air of new things being botched onto a creaking frame. Support for unit testing is an afterthought, there is some integration of source control into the Matlab environment but it is with Source Safe. It doesn’t support namespaces. It doesn’t support common data structures such as dictionaries, lists and sets.
  • The toolbox ecosystem is heavily focused on scientific applications, generally in the physical sciences. So there is no support for natural language processing, for example, or building a web application based on the powerful analysis you can do elsewhere in the ecosystem;
  • the licensing is a nightmare. Once you’ve got core Matlab additional toolboxes containing really useful functionality (statistics, database connections, a “compiler”) are all at an additional cost. You can investigate pricing here. In my experience you often find yourself needing a toolbox for just a couple of functions. For an academic things are a bit rosier, universities get lower price licenses and the process by which this is achieved is opaque to end-users. As an industrial user, involved in the licensing process, it is as bad as line management and sticking needles in your eyes in the “not much fun thing to do” stakes;
  • running Matlab with network licenses means that your code may stop running part way through because you’ve made a call to a function to which you can’t currently get the license. It is difficult to describe the level of frustration and rage this brings. Now of course one answer is to buy individual licenses for all, or at least a significant surplus of network licenses. But tell that to the budget holder particularly when you wanted to run the analysis today. The alternative is to find one of the license holders of the required toolbox and discover if they are actually using it or whether they’ve gone off for a three hour meeting leaving Matlab open;
  • deployment to users who do not have Matlab is painful. They need to download a more than 500MB runtime, of exactly the right version and the likelihood is they will be installing it just for your code;

I started programming in Python at much the same time as I started on Matlab. At the time I scarcely used it for analysis but even then when I wanted to parse the HTML table of contents for Physical Review E, Python was the obvious choice. I have written scrapers in Matlab but it involved interfering with the Java underpinnings of the language.

Python has matured since my early use. It now has a really great system of libraries which can be installed pretty much trivially, they extend far beyond those offered by Matlab. And in my view they are of very good quality. Innovation like IPython notebooks take the Matlab interactive style of analysis and extend it to be natively web-based. If you want a great example of this, take a look at the examples provided by Matthew Russell for his book, Mining the Social Web.

Python is a modern language undergoing slow, considered improvement. That’s to say it doesn’t carry a legacy stretching back decades and changes are small, and directed towards providing a more consistent language. Its used by many software developers who provide a source of help, support and an impetus for an decent infrastructure.

Ubuntu users will find Python pre-installed. For Windows users, such as myself, there are a number of distributions which bundle up a whole bunch of libraries useful for scientists and sometimes an IDE. I like python(x,y). New libraries can generally be installed almost trivially using the pip package management system. I actually use Python in Ubuntu and Windows almost equally often. There are a small number of libraries which are a bit more tricky to install in Windows – experienced users turn to Christoph Gohlke’s fantastic collection of precompiled binaries.

In summary, Matlab brought much to data analysis for scientists but its time is past. An analysis environment built around Python brings wider functionality, a better coding infrastructure and freedom from licensing hell.

Aug 23 2014

Book review: Greenwich Time and the Longitude by Derek Howse

greenwich_timeI am being used as a proxy reader! My colleague drj, impressed by my reviewing activities, asked me to read Greenwich Time and the Longitude by Derek Howse, so that he wouldn’t have to.

There was some risk here that Greenwich Time and the Longitude would overlap heavily with Finding Longitude which I have recently read. They clearly revolve around the same subjects and come from the same place: the National Maritime Museum at Greenwich. Happily the overlap is relatively minor. Following some brief preamble regarding the origins of latitude and longitude for specifying locations, Greenwich Time starts with the founding of the Royal Observatory at Greenwich.

The Observatory was set up under Charles II who personally ordered it’s creation in 1675, mindful of the importance of astronomy to navigation. The first Royal Astronomer was John Flamsteed. Accurate measurement of the locations of the moon and stars was a prerequisite for determining the longitude at sea both by lunar-distance and clock based means. Flamsteed’s first series of measurements was aimed at determining whether the earth rotated at a constant rate, something we take for granted but wasn’t necessarily the case.

Flamsteed is notorious for jealously guarding the measurements he made, and fell out with Isaac Newton over their early, unauthorised publication which Newton arranged. A detail I’d previously missed in this episode is that Flamsteed was not very well remunerated for his work, his £100 per annum salary had to cover the purchase of instruments as well as any skilled assistance he required which goes some way to explaining his possessiveness over the measurements he made. 

Greenwich Time covers the development of marine chronometers in the 18th century and the period of the Board of Longitude relatively quickly.

The next step is the distribution of time. Towards the middle of the 19th century three industries were feeling the need for precise timekeeping: telegraphy, the railways and the postal service. This is in addition to the requirements of marine navigators. The first time signal, in 1833, was distributed by the fall of a large painted zinc ball on the top of the Greenwich observatory. Thereafter, strikingly similar balls appeared on observatories around the world.

From 1852 the time signal was distributed by telegraphic means, and ultimately by radio. It was the radio time signal that ultimately brought an end to the publication of astronomical tables for navigation. Britain’s Nautical Almanac, started in 1767, stopped publishing them in 1907 – less than 10 years after the invention of radio.

With the fast distribution of time signals over large distances came the issue of the variation between local time (as defined by the sun and stars) and the standard time. The problem was particularly pressing in the United States which spanned multiple time zones. The culmination of this problem is the International Date Line, which passes through the Pacific. Here the day of the week changes on crossing the line, a problem discovered by the very first circumnavigators (Magellan’s expedition in 1522), identified when they reached travellers who had arrived from the opposite direction and disagreed on the day of the week. I must admit to being a bit impressed by this, I can imagine it’s easy to lose track of the days on such an expedition.

I found the descriptions of congresses to standardise the meridian and time systems across multiple nations in the 1880s rather dull.

One small thing of interest in these discussions: mariners used to measure the end of the day at noon, hence what we would call “Monday morning” a mariner would call “the end of Sunday”, unless he was at harbour – in which case he would use local time! It is from 18th century mariners that Jean Luc Picard appears to get his catchphrase “Make it so!”, this was the traditional response of a captain to the officer making the noon latitude measurement. The meridian congresses started the process of standardising the treatment of the day by “civilians”, mariners and astronomers.

The book finishes with a discussion of high precision timekeeping. This is where we discover that Flamsteed wasn’t entirely right when he measured the earth to rotate at a constant rate. The earth’s rotation is showing a long term decrease upon which are superimposed irregular variations and seasonal variations. And the length of the year is slowly changing too. Added to that, the poles drift by about 8 metres or so over time. It’s testament to our abilities that we can measure these imperfections but somehow sad that they exist.

The book has an appendix with some detail on various measurements.

Not as sumptuous a book as Finding Longitude it is an interesting read with a different focus. It has some overlap too with The History of Clocks and Watches by Eric Bruton.

Aug 18 2014

Book review: Degrees Kelvin by David Lindley

How to start? I’ve read another book… degrees_kelvinDegrees Kelvin: A tale of genius, invention and tragedy by David Lindley. This is a biography of William Thomson, later Lord Kelvin, who lived 1824-1907.

Thomson lived at a time when the core of classical physics came into being, adding thermodynamics and electromagnetism to Newtonian mechanics. He played a significant role in creating these areas of study. As well as this he acted as a scientific advisor in the creation of the transatlantic telegraph, electric power transmission, marine compasses and a system of units for electromagnetism. He earned a substantial income from patents relating to telegraphy and maritime applications, and bought a blingy yacht (the Lalla Rookh) with the money.

He died a few years after the discovery of radioactivity, x-rays, special relativity and the first inklings of quantum mechanics – topics that were to form “modern physics”.

The book starts with William Thomas heading off to Cambridge to study maths. Prior to going he has already published in a mathematical journal on Philip Kelland’s misinterpretation of Fourier’s work on heat.

His father, James Thomson is a constant presence through his time in Cambridge in the form of a stream of letters, these days he’d probably be described as a “helicopter parent”. James Thomson is constantly concerned with his son falling in with the wrong sort at university, and with the money he is spending. James Thomson was a professor of mathematics at Glasgow University, William had attended his classes at the university along with his brother. Hence his rapid entry into academic publishing.

Fourier’s work Analytical Theory of Heat is representative of a style of physics which was active in France at the beginning of the 19th century. He built a mathematical model of the flow of heat in materials, with techniques for calculating the temperature throughout that body – one of which were the Fourier series – still widely used by scientists and engineers today. For this purpose the fundamental question of what heat was could be ignored. Measurements could be made of heat flow and temperature, and the model explained these outward signs. Fourier’s presentation was somewhat confused, which led Philip Kelland – in his book Theory of Heat to claim he was wrong. Thomson junior’s contribution was to clarify Fourier’s presentation and point out, fairly diplomatically, that Kelland was wrong. 

Slightly later the flow of letters from Thomson senior switches to encourage his son into the position held by the ailing William Meikleham, Professor of Natural Philosophy at Glasgow University – this project is eventually successful when Meikleham dies and Thomson takes the post in 1846. He retired from his position at Glasgow University in 1899.

William Thomson appears to have been innovative in teaching, introducing the laboratory class into the undergraduate degree, and later writing a textbook of classical physics, Treatise on Natural Philosophy, with his friend P.G. Tait.

Following his undergraduate studies at Cambridge, William goes to Paris, meeting many of the scientific community there at the time and working in the laboratory of Henri Regnault on thermodynamics. In both thermodynamics and electromagnetism Thomson plays a role in the middle age of the topic, not there at the start but not responsible for the final form of the subject. In both thermodynamics and electromagnetism Thomson’s role was in the “formalisation” of the physical models made by others. So he takes the idea of lines of force from Faraday’s electrical studies and makes them mathematical. The point of this exercise is that now the model can be used to make quantitative predictions in complex situations of, for example, the transmission of signals down submarine telegraph wires.

Commercial telegraphy came in to being around 1837, the first transatlantic cable was strung in 1857 – although it only worked briefly, and poorly for a few weeks. The first successful cable was laid in 1866. It’s interesting to compare this to the similarly rapid expansion of the railways in Britain. Thomson played a part from the earliest of the transatlantic cables. Contributing both theoretically and practically – he invented and patented the mirror galvanometer which makes reading weak signals easier.

It’s a cliché to say “X was no stranger to controversy” Thomson had his share – constantly needling geologists over the age of the earth and getting into spats regarding priority of James Joule on the work on inter-convertibility of energy. It sounds like he bears some responsibility for the air of superiority that physicists can sometime display over the other sciences. Although it should be said that he more played second fiddle to the more pugnacious P.G. Tait.

Later in life Thomson struggled to accept Maxwell’s formulation of electromagnetic theory, finding it too abstract – he was only interested in a theory with a tangible physical model beneath it. Maxwell’s theory had this at the start, an ever more complex system of gear wheels, but ultimately he cut loose from it. As an aside, the Maxwell’s equations we know today are very much an invention of Oliver Heaviside who introduced the vector calculus notation which greatly simplifies their appearance, he too cut his teeth on telegraphy.

At one point Lindley laments the fact Lord Kelvin has not had the reputation he deserves since his death. Reputation is a slippery thing, recognition amongst the general public is a fickle and no real guide to anything. Most practicing scientists pay little heed to the history of their subject, fragments are used as decoration for otherwise dull lectures.

It’s difficult to think of modern equivalents of William Thomson in science, his theoretical role is similar to that of Freeman Dyson or Richard Feynman. It’s not widely recognised but Albert Einstein, like Thomson, was active in making patent applications but does not seem to have benefitted financial from his patents. Thomson also plays the role of Victorian projector, such as Isambard Kingdom Brunel. Projects in the 21st century are no longer so obviously the work of one scientist/engineer/project manager/promoter these roles having generally been split into specialisms. 

I was intrigued to discover that Lindley apparently uses S.P. Thompson’s 1910 biography of Kelvin as his primary source, not mentioning at all the two volume Energy and Empire by Crosbie Smith and M. Norton Wise published in 1989.

Degrees Kelvin provides a useful entry into physics and technology in the 19th century, I am now curious about the rise of electricity and marine compasses!

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