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!

Aug 03 2014

Book review: Finding Longitude by Richard Dunn, Rebekah Higgitt

finding-longitudeMuch of my reading comes via twitter in the form of recommendations from historians of science, in this case I am reading a book co-authored by one of those historians: Finding Longitude by Richard Dunn (@lordoflongitude) and Rebekah Higgitt (@beckyfh).

I must admit I held off buying Finding Longitude for a while since it appeared to be an exhibition brochure, maybe not so good if you haven’t attended the exhibition. It turns out to be freestanding and perfectly formed.This is definitely the most sumptuous book I’ve bought in quite some time, I’m glad I got the hardcover version rather than the Kindle edition.

The many photographs throughout the book are absolutely gorgeous, they are of the instruments and clocks, the log books, artwork from the time. You can get a flavour from the images online here.

To give some context to the book, knowing your location on earth is a matter of determining two parameters: latitude and longitude:

  • latitude is your location in the North-South direction between the equator and either of the earth’s poles, it is easily determined by the height of the sun or stars above the horizon, and we shall speak no more of it here.
  • longitude is the second piece of information required to specify ones position on the surface of the earth and is a measure your location East-West relative to the Greenwich meridian. The earth turns at a fixed rate and as it does the sun appears to move through the sky. You can use this behaviour to fix a local noon time: the time at which the sun reaches the highest point in the sky. If, when you measure your local noon, you can also determine what time it is at some reference point Greenwich, for example, then you can find your longitude from the difference between the two times.

Knowing where you are on earth by measurement of these parameters is particularly important for sailors engaged in long distance trade or fighting. It has therefore long been an interest of governments.

The British were a bit late to the party in prizes for determining the longitude, the first of them had been offered by Phillip II of Spain in 1567 and there had been activity in the area since then, primarily amongst the Spanish and Dutch. Towards the end of the 17th century the British and French get in on the act, starting with the formation of the Royal Society and Académie des sciences respectively.

One stimulus for the creation of a British prize for determining the longitude was the deaths of 1600 British sailors from Admiral Sir Cloudsley Shovell’s fleet off the Isles of Scilly in 1707. They died on the rocks off the Isles of Scilly in a storm, as a result of not knowing where they were until it was too late. As an aside, the surviving log books from Shovell’s fleet showed that for the latitude (i.e. the easier thing to measure), measurements of the sun gave a 25 mile spread, and those from dead reckoning a 75 mile spread in location.

The Longitude Act was signed into law in 1714, it offered a prize of £20,000 to whoever produced a practicable method for determining the longitude at sea. There was something of the air that it was a problem about to be solved. The Board of Longitude was to judge the prize. The known competitor techniques at the time were timekeeping by mechanical means, two astronomical methods (the lunar distance method, and the satellites of Jupiter) and dead-reckoning. In fact these techniques are used in combination, mechanical timekeepers are simpler to use than the astronomical methods but mechanical timekeepers needed checking against the astronomical gold standard which was the only way to reset a stopped clock. Dead-reckoning (finding your location by knowing how fast you’d gone in what direction) was quick and simple, and worked in all weathers. Even with a mechanical timekeeper astronomical observations were required to measure the “local” time, and that didn’t work in thick cloud.

There’s no point in sailors knowing exactly where they were if maps did not describe exactly where the places where they were going, or trying to avoid. Furthermore, the lunar distance method of finding longitude required detailed tables of astronomical data which needed updating regularly. So alongside the activities of the longitude projectors, the state mechanisms for compiling charts and making astronomical tables were built up.

John Harrison and his timepieces are the most famous part of the longitude story. Harrison produced a series of clocks and watches from 1730 and 1760, in return he received moderate funding over the period from the Board of Longitude, you can see the payment record in this blog post here. Harrison felt hard done by since his final watches met the required precision but the Board of Longitude were reluctant to pay the full prize. Although meeting the technical specification in terms of their precision were far from a solution. Despite his (begrudging) efforts, they could not be reliably reproduced even by the most talented clock makers.

After Harrison’s final award several others made clocks based on his designs, these were tested in a variety of expeditions in the latter half of the 18th century (such as Cook’s to Tahiti in 1769). The naval expedition including hydrographers, astronomers, naturalists and artists became something of a craze (see also Darwin’s trip on the Beagle). As well as clocks, men such as Jesse Ramsden were mass producing improved instruments for navigational measurements, such as octants and sextants.

The use of chronometers to determine the longitude was not fully embedded into the Royal Navy until into the 19th century with the East Indian Company running a little ahead of them by having chronometers throughout their fleet by 1810. 

Finding Longitude is a a good illustration of providing the full context for the adoption of a technology. It’s the most beautiful book I’ve read in while, and it doesn’t stint on detail.

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