Tag: history of science

Aug 25 2013

Book review: A history of the world in twelve maps by Jerry Brotton

HistoryOfTheWorldInTwelveMapsAs a fan of maps, I was happy to add A History of the World in Twelve Maps by Jerry Brotton to my shopping basket (I bought it as part of a reduced price multi-buy deal in an actual physical book shop).

A History traces history through the medium maps, various threads are developed through the book: what did people call the things we now call maps? what were they trying to achieve with their maps? what geography was contained in the maps? what technology was used to make the maps?

I feel the need to explicitly list, and comment on, the twelve maps of the title:

1. Ptolemy’s Geography 150 AD, distinguished by the fact that it probably contained no maps. Ptolemy wrote about the geography of the known world in his time, and amongst this he collated a list of locations which could be plotted on a flat map using one of two projection algorithms. A projection method converts (or projects) the real life geography of the spherical earth onto the 2D plane of a flat map. Project methods are all compromises, it is impossible to simultaneously preserve relative directions, areas and lengths when making the 3D to 2D transformation. The limitation of the paper and printing technology to hand meant that Ptolemy was not able to realise his map. Also the relatively small size of the known world meant that projection was not a pressing problem. The Geography exists through copies created long after the original was written.

2. Al-idrisi’s Entertainment, 1154AD. The Entertainment is not just a map, it is a description of the world as it was known at the time. This was the early pinnacle in terms of the realisation of the roadmap laid out by Ptolemy. Al-Idrisi, a Muslim nobelman, made the Entertainment for a Christian Sicilian king. It draws on both Christian and Muslim sources to produce a map which will look familiar to modern eyes (except for being upside down). There is some doubt as to exactly which map was included in the Entertainment since no original intact copies exist.

3. Hereford Mappamundi, 1300AD this is the earliest original map in the book but in many ways it is a step backward in terms of the accuracy of its representation of the world. Rather than being a geography for finding places it is a religious object placing Jerusalem at the top and showing viewers scenes of pilgrimage and increasing depravity as one moves away from salvation. It follows the T-O format which was common among such mappmundi.

4. Kangnido world map, 1402AD. To Western eyes this is a map from another world: Korea, again it only exists in copies but not that distant from the original. Here we see strongly the influence of the neighbouring China. The map is about administration and bureaucracy (and contains errors thought to have been added to put potential invaders off the scent). An interesting snippet is that the Chinese saw the nonogram (a square made of 9 squares) as the perfect form – in a parallel with the Greek admiration for the circle. The map also contains elements of geomancy, which was important to the Koreans.

5. Waldseemuller world map, 1507AD. This is the first printed map, it hadn’t really struck me before but printing has a bigger impact than simply price and availability when compared to manuscripts. Printed books allow for all sorts of useful innovations such as pagination, indexes, editions and so forth which greatly facilitate scholarly learning. With manuscripts stating that something is on page 101 of you handwritten manuscript is of little use to someone else with his handwritten copy of the same original manuscript. The significance of the Waldseemuller map is that it is the first European map to name America, it applies the label to the south but it is sometimes seen as the “birth certificate” of the USA. Hence the US Library of Congress recently bought it for $10 million.

6. Diogo Ribeiro, world map, 1529AD. A map to divide the world between the Spanish and Portuguese, who had boldly signed a treaty dividing the world into two hemispheres with them to own one each. The problem arose on the far side of the world, where it wasn’t quite clear where the lucrative spice island of Moluccas lay.

7. Gerard Mercator world map, 1569AD. I wrote about Mercator a while back, in reviewing The World of Gerard Mercator by Andrew Taylor. The Mercator maps are important for several reasons, they introduce new technology in the form of copperplate rather than woodcut printing, copperplate printing enables italic script, rather than the Gothic script that is used in woodcut printing; they make use of the newly developed triangulation method of surveying (in places); the Mercator projection is one of several methods developed at the time for placing a spherical world onto a flat map – it is the one that maintained – despite limitations.And finally he brought the Atlas to the world – a book of maps.

8. Joan Blaeu Atlas maier, 1662. Blaeu was chief cartography for the Dutch East India Company (VOC), and used the mapping data his position provided to produce the most extravagant atlases imaginable. They combined a wide variety of previously published maps with some new maps and extensive text. These were prestige objects purchased by wealthy merchants and politicians.

9. Cassini Family, map of France, 1793. The Cassini family held positions in the Paris Observatory for four generations, starting in the late 17th Century when the first geodesic studies were conducted, these were made to establish the shape of the earth, rather than map it’s features. I reviewed The Measure of the Earth  by Larry D. Ferriero which related some of this story. Following on from this the French started to carry systematic triangulation surveys of all of France. This was the first time the technique had been applied at such scale, and was the forbearer to the British Ordnance Survey, the origins of which are described in Map of a Nation by Rachel Hewitt. The map had the secondary effect of bringing together France as a nation, originally seen by the king as a route to describing his nation (and possibly taxing it), for the first time Parisian French was used to describe all of the country and each part was mapped in an identical manner.

10. The Geographical Pivot of History, Halford Mackinder, 1904. In a way the Cassini map represents the pinnacle of the technical craft of surveying. Mackinder’s intention was different, he used his map to persuade. He had long promoted the idea of geography as a topic for serious academic study and in 1904 he used his map to press his idea of central Asia as being central to the politics and battle for resources in the world. He used a map to present this idea, its aspect and details crafted to reinforce his argument.

11. The Peters Projection, 1973. Following the theme of map as almost-propaganda the Peters projection – an attempted equal-area projection – shows a developing world much larger than we are used to in the Mercator projection. Peters attracted the ire of much of the academic cartographic communities, partly because his projection is nothing new but also because he promoted it as being the perfect, objective map when, in truth it was nothing of the kind. This is sort of the point of the Peters projection, it is open to criticism but highlights that the decisions made about the technical aspects of a map have a subjective weight. Interestingly, many non-governmental organisations took to using the Peters projection because it served their purpose of emphasising the developing world.

12. Google Earth, 2012. The book finishes with a chapter on Google Earth, initially on the technical innovations required to make such a map but then moving on to the wider commercial implications. Brotton toys with the idea that Google Earth is somehow “other“ from previous maps in its commercial intent and the mystery of its methods, this seems wrong to me. A number of the earlier maps he discusses were of limited circulation and one does not get the impression that methods were shared generously. Brotton makes no mention of the Openstreetmap initiative that seems to address these concerns.

In the beginning I found the style of A History a little dry and academic but once I’d got my eye in it was relatively straightforward reading. I liked the broader subject matter, and greater depth than some of my other history of maps reading.

Jun 29 2013

Book review: Chasing Venus by Andrea Wulf

ChasingVenusI’ve been reading more of adventurous science of the Age of Enlightenment, more specifically Andrea Wulf’s book Chasing Venus: The Race to Measure the Heavens the scientific missions to measure the transit of Venus in 1761 and 1769.

Transits occur when a planet, typically Venus, lies directly between the earth and the Sun. During a transit Venus appears as a small black disc on the face of the sun. Since it’s orbit is also inside that of earth Mercury also transits the sun. Solar eclipses are similar but in this case the obscuring body is the moon, and since it is much closer to earth it completely covers the face of the sun.

Transits of Venus occur in pairs, 8 years apart separated by 100 or so years, they are predictable astronomical events. Edmund Halley predicted the 1761/1769 pair in 1716 and in addition proposed that the right type of observation would give a measure of the distance from the earth to the Sun. Once this distance is known distances of all the other planets from the sun can be calculated. In the same way as a solar eclipse can only be observed from a limited number of places on earth, the transit of Venus can only be observed from a limited number of places on earth. The observations required are the time at which Venus starts to cross the face of the sun, ingress, and the time at which it leaves, egress. These events are separated by several hours. In order to calculate the distance to the sun observations must be made at widely separate locations.

These timings had to be globally calibrated: some one in, say, London, had to be able to convert the times measured in Tahiti to the time London. This amounts to knowing precisely where the measurement was made – it is the problem of the longitude. At this time the problem of the longitude was solved given sufficient time, for land-based locations. It was still a challenge at sea.

At the time of the 1761/69 transits globe spanning travel was no easy matter, when Captain Cook landed on Tahiti in 1769 his was only the third European vessel to have done so, other ships had arrived in the two previous years; travel to the East Indies although regular was still hazardous. Even travel to the far North of Europe was a challenge, similarly across Russia to the extremes of Siberia. Therefore much of the book is given over to stories of long, arduous travel not infrequently ending in death.

Most poignant for me was the story of Jean-Baptiste Chappe d’Auteroche who managed to observe the entirety of both transits in Siberia and California but died of typhus shortly after observing the lunar eclipse critical to completing the observations he had made of Venus. His fellow Frenchman, Guillaume Joseph Hyacinthe Jean-Baptiste Le Gentil, observed the first transit onboard a ship on the way to Mauritius (his measurements were useless), remained in the area of the Indian Ocean until the second transit which he failed to observe because of the cloud cover and returned to France after 10 years, his relatives having declared him dead and the Académie des Sciences ceasing to pay him, assuming the same. Charles Green, observing for the Royal Society from Tahiti with Captain Cook and Joseph Banks, died after falling ill in Jakarta (then Batavia) after he had made his observations.

The measurements of the first transit in 1761 were plagued by uncertainty, astronomers had anticipated that they would be able to measure the times of ingress and egress with high precision but found that even observers at the same location with the same equipment measured times differing by 10s of seconds. We often see sharp, static images of the sun but viewed live through a telescope the picture is quite different; particularly close to the horizon the view of the sun the sun boils and shimmers. This is a result of thermal convection in the earth’s atmosphere, and is known as “seeing”. It’s not something I’d appreciated until I’d looked at the sun myself through a telescope. This “seeing” is what caused the problems with measuring the transit times, the disk of Venus did not cross a sharp boundary into the face of the sun, it slides slowly into a turbulent mess.

The range of calculated earth-sun distances for the 1761 measurements was 77,100,000 to 98,700,000 miles which spans the modern value of 92,960,000 miles. This represents a 22% range. By 1769 astronomers had learned from their experience, and the central estimate for the earth-sun distance by Thomas Hornsby was 93,726,000 miles, a discrepancy of less than 1% compared to the modern value. The range of the 1769 measurements was 4,000,000 miles which is only 4% of the earth-sun distance.

By the time of the second transit there was a great deal of political and public interest in the project. Catherine the Great was very keen to see Russia play a full part in the transit observations, in England George III directly supported the transit voyages and other European monarchs were equally keen.

Chasing Venus is of the same theme as a number of books I have reviewed previously: The Measure of the Earth, The Measure of All Things, Map of a Nation, and The Great Arc. The first two of these are on the measurement of the size, and to a degree, the shape of the Earth. The first in Ecuador in 1735, the second in revolutionary France. The Great Arc and Map of a Nation are the stories of the mapping by triangulation of India and Great Britain. In these books it is the travel, and difficult conditions that are the central story. The scientific tasks involved are simply explained, although challenging to conduct with accuracy at the time they were made and technically complex in practice.

There is a small error in the book which caused me initial excitement, the first transit of Venus was observed in 1639 by Jeremiah Horrocks and William Crabtree, Horrocks being located in Hoole, Cheshire according to Wulf. Hoole, Cheshire is suburb of Chester about a mile from where I am typing this. Sadly, Wulf is wrong, Horrocks appears to have made his observations either at Carr House in Bretherton or Much Hoole (a neighbouring village) both in Lancashire and 50 miles from where I sit.

Perhaps unfairly I found this book a slightly repetitive list of difficult journeys conducted first in 1761, and then in 1769. It brought home to me the level of sacrifice for these early scientific missions, and indeed global trade, simply in the separation from ones family for extended periods but quite often in death.

Mar 26 2013

Book review: The Dinosaur Hunters by Deborah Cadbury

DinosaurHuntersA rapid change of gear for my book reviewing: having spent several months reading “The Eighth Day of Creation” I have completed “The Dinosaur Hunters” by Deborah Cadbury in only a couple of weeks. Is this a bad thing? Yes, and no – it’s been nice to read a book that rattles along at a good pace, is gripping and doesn’t have me leaping to make notes at every page – the downside is that I feel I have consumed a literary snack rather than a meal.

The Dinosaur Hunters covers the initial elucidation of the nature of large animal fossils, principally of dinosaurs, from around the beginning of the 19th century to just after the publication of Darwin’s “Origin of the Species” in 1859. The book is centred around Gideon Mantell (1790-1852) who first described the Iguanodon and was an expert in the geology of the Weald, at the same time running a thriving medical practice in his home town of Lewes. Playing the part of Mantell’s nemesis is Richard Owen (1804-1892), who formally described the group of species, the Dinosauria, and was to be the driving force in the founding of the Natural History Museum in the later years of the 19th century. Smaller parts are played by Mary Anning (1799-1847), fossil collector based in Lyme Regis; William Buckland (1784-1856) who described Megalosaurus – the first of the dinosaurs and spent much of his life trying to reconcile his Christian faith with new geological findings; George Cuvier (1769-1832) the noted French anatomist who related fossil anatomy to modern animal anatomy and identified the existence of extinctions (although he was a catastrophist who saw this as evidence of different epochs of extinction rather than a side effect of evolution); Charles Lyell (1897-1875) a champion of uniformitarianism (the idea that the modern geology is the result of processes visible today continuing over great amounts of time); Charles Darwin (1809-1882) who really needs no introduction, and Thomas Huxley (1825-1895) a muscular proponent of Darwin’s evolutionary theory.

For me a recurring theme was that of privilege and power in science, often this is portrayed as something which disadvantaged women but in this case Mantell is something of a victim too, as was William Smith as described in “The Map that Changed the World”. Mantell was desperate for recognition but held back by his full-time profession as a doctor in a minor town and his faith that his ability would lead automatically to recognition. Owen, on the other hand, with similar background (and prodigious ability) went first to St Bartholomew’s hospital and then the Royal College of Surgeon’s where he appears to have received better patronage but in addition was also brutal and calculating in his ambition. Ultimately Owen over-reached himself in his scheming, and although he satisfied his desire to create a Natural History Museum, in death he left little personal legacy – his ability trumped by his dishonesty in trying to obliterate his opponents.

From a scientific point of view the thread of the book is from the growing understanding of stratigraphy i.e. the consistent sequence of rock deposits through Great Britain and into Europe; the discovery of large fossil animals which had no modern equivalent; the discovery of an increasing range of these prehistoric remnants each with their place in the stratigraphy and the synthesis of these discoveries in Darwin’s theory of evolution. Progress in the intermediate discovery of fossils was slow because in contrast to the the early fossils of marine species such as icthyosaurus and plesiosaurus which were discovered substantially intact later fossils of large land animals were found fragmented in Southern England, which made identifying the overall size of such species and even the numbers of species present in your pile of fossils difficult.

These scientific discoveries collided with a social thread which saw the clergy deeply involved in scientific discovery at the beginning, becoming increasingly discomforted with the account of the genesis of life in Scripture being incompatible with the findings in the stone. This ties in with a scientific community trying to make their discoveries compatible with Scripture and what they perceived to be the will of God with the schism between the two eventually coming to a head by the publication of Darwin’s Origin of Species.

Occasionally the author drops into a bit of first person narration which I must admit to finding a bit grating, perhaps because for people long dead it is largely inference. I’d have been very happy to have chosen this book for a long journey or a holiday, I liked the wider focus on a story rather than an individual.

References

My Evernotes

Mar 14 2013

Book review: The Eighth Day of Creation by Horace Freeland Judson

EighthDayMy reading moves seamlessly from the origins of cosmology (in Koestler’s Sleepwalkers) to the origins of molecular biology in “The Eighth Day of Creation” by Horace Freeland Judson. The book covers the revolution in biology starting with the elucidation of the structure of DNA through to how this leads to the synthesis, by organisms, of proteins – this covers a period from just before the Second World War to the early 1960s although in the Epilogue and Afterwords. Judson comments on the period up to the mid-nineties. Although the book does provide basic information on the core concepts (What is DNA? What is a protein?), I suspect it requires a degree of familiarity with these ideas to make much sense on a casual reading – the same applies to this blog post.

The first third or so of the book covers the elucidation of the structure of DNA. Three groups were working on this problem – that of Linus Pauling in the US, Franklin and Wilkins at Kings College in London and Crick and Watson in Cambridge. Key to the success of Crick and Watson was their collaboration: a willingness to talk to people who knew stuff they needed to know, and piecing the bits together. The structural features of their model were the helix form (this wasn’t news), specific and strong hydrogen bonding between bases, and the presence of two DNA chains (running in opposite directions). On the whole this wasn’t a new story to me, although I wasn’t familiar with the surrounding work which established DNA as the genetic material. Judson returns to the part Rosalind Franklin in the discovery in one of the Afterwords. It has been said that Franklin was greatly wronged over the discovery of DNA, but Judson does not hold this view and I tend to agree with him. The core of the problem is that the Nobel Prize is not awarded posthumously, and with her death at 37 from cancer, Franklin therefore missed out. Watson’s book The Double Helix was a rather personalised view of the characters involved most of whom were alive to carry out damage limitation, whilst Franklin was not – so here she was poorly treated but by Watson rather than a whole community of scientists. Perhaps the thing that said the most to me about the situation is that after she was diagnosed with cancer she stayed with Cricks at their home.

In parallel with the elucidation of the structure of the DNA work had been ongoing with understanding protein synthesis and genetics in viruses and bacteria. This included both how information was coded into DNA, with much effort expended in trying to establish overlapping codes. There are 20 amino acids and four bases in DNA, so three base pairs are required to specify an amino acid if the amino acid sequence is to be unconstrained but it was conceivable that two consecutive amino acids are coded by fewer than 6 base pairs but in this case there is a restriction on the possible amino acid sequences. This area was initiated by the physicist, George Gamow. I struggle a bit to see how it gained so much traction, this type of model was quickly ruled out by consideration of the amino acid sequences that we being established for proteins at the time. It turns out that amino acids are coded by three consecutive base pairs with redundancy (so several different base pair triplets code for the same amino acid). Also covered was the mechanism by which data passed from DNA to the ribosomes where protein synthesis takes place, important here are adaptor molecules which carry the appropriate amino acid to the site of synthesis.

Compared to the structure of DNA this work was a long difficult slog, involving intricate experiments with bacteria, bacteriophage viruses, bacterial sex, ultracentrifugation, chromatography and radiolabelling.

The final part of the book is on the elucidation of the structure of proteins, this was done using x-ray crystallography with the very first clear scattering patterns measured in the 1930s and the first full elucidation made in the late fifties. X-ray crystallography of proteins, containing many thousands of atoms is challenging. Fundamentally there is a issue, the “phase problem”, which means you don’t have quite enough information to determine the structure from the scattering pattern. This issue was resolved by heavy atom labelling, here you try to chemically attach a heavy atom such as mercury to your protein then compare the scattering pattern of this modified protein with that of the unmodified protein, which resolves the phase problem. Nowadays measuring the thousands of spots in an x-ray scattering pattern and carrying out the thousands and thousands of calculations required to resolve the structure is relatively straightforward but in the early days it was a massive manual labour.

As well as resolving structure a key discovery was made regarding the mode of action of proteins: essentially they work as adaptors between chemical distinct systems – when a molecule binds to one site on a protein it effects the ability of another type of molecule to bind to another site on the protein through changes in the protein structure induced by the first molecule’s binding. This feature opens up huge possibilities for cell biology – in the absence of this feature interactions between chemical systems can only occur if the participants in those systems interact with each other chemically.

It isn’t something I’d really appreciated properly but molecular biologists are quite organised in the organisms that they generally agree to work on. The truth is that there are uncountably many viruses and so to aid the progress of science one needs to select which ones to study: E. Coli, the T series bacteriophages, C. Elegans, D. Melanogaster and more recently the zebrafish, they almost play the part of an extra author.

Molecular biology was apparently dominated by physicists, I must admit I found this confusing in the past but Judson highlights the field as defined by its practioners: biochemistry is about energy and matter (and typically small molecules), molecular biology is about information (and typically macromolecules) – a more natural home for physicists.

I found the first and third parts an enjoyable read, my scientific background is in scattering so the technical material was at least familiar the central section on genetics I found fascinating but a bit of a slog. I’m somewhat in awe of the complexity of the experiments (and their apparent difficulty).

Looking back on my earlier book reviews, I read my comment on R.J. Evan’s book on historiography that history is a literary exercise as well as anything else, as a trained scientist this was something of an alien concept but in common with Koestler’s book the style of this book shines through.

 

Footnotes

My Evernotes