Scenic Devon – and Oxbridge!

The last few days have provided plenty of photographic opportunities – so I’m letting the pictures do most of the talking this time.

While Jen was at a conference in Seattle last week, I went on retreat to Lee Abbey in north Devon. As the weather was so good, I went on a couple of walks as well – the scenery around there is amazing!

North Devon coast near Lynmouth

North Devon coast near Lynmouth


North Devon coast near Lynmouth

I wasn’t doing much bird-watching, but on one of the afternoons there was a very obliging wheatear near Lee Abbey which required some serious attention…

Wheatear near Lee Abbey

Wheatear near Lee Abbey

At the weekend, Jen and I headed off to Cambridge, to see Uta Hill and her family. While we were there Jen showed me some of Trinity College, where she studied.

It looked like such a calm, idyllic day... sunshine, students and tourists punting on the river Cam, Jen in front of Trinity College...

It looked like such a calm, idyllic day… sunshine, students and tourists punting on the river Cam, Jen in front of Trinity College…

...and then two boats collided, and the idyll was nearly shattered.

…and then two punts collided right by us, nearly bringing the idyll to a soggy end.

On our way back to Somerset, we went to visit my aunt, Rosalie, in Kennington, on the edge of Oxford. While there we went for a short walk down to the river Thames at Sandford Lock – the evening light was great so I couldn’t resist taking a few more photos!

Jen at Sandford Lock on the river Thames

Jen at Sandford Lock on the river Thames

Of violins, quesadillas and phalaropes

On Saturday, Jen was part of the All Souls orchestra in their Christmas Praise event – and for me it was a much more relaxed occasion than the one last year! Back then, we were meeting for the second time, and Jen was keen for me to have lunch with some of her friends (Katie, AnnaMarie and Sharon)… an event I have since affectionately called ‘meeting the committee’!

Jen among the first violins in the All Sould Orchestra.

Jen among the first violins in the All Souls Orchestra.

The concert is a blend of traditional carols and other pieces of Christmas music from elsewhere – such as the Angel’s carol by John Rutter, Walking in a winter wonderland, and a selection from West side story. This year the orchestra was joined by West End Has Faith, a group of Christians who work professionally as actors and singers in London’s west end and further afield. While I enjoyed last year’s concert, this one seemed even better – the creative blend of those involved worked particularly well.

The All Souls Christmas Priase event in full swing

The All Souls Christmas Priase event in full swing

Carlos, Lilia and Jen

Carlos, Lilia and Jen

The previous evening, Jen and I were taken to a Mexican restaurant by Carlos and Lilia. Carlos is a lecturer from Colima on the west coast of Mexico, who is having a sabbatical year at Imperial College. He was keen for us to experience ‘real’ Mexican food, as opposed to the Tex-Mex that is popularised by a some well known restaurant chains, so we went to Lupita near Charing Cross station. It was a most enjoyable meal, particularly because we were guided by them as to what were the best dishes to try. I was keen to try cactus, which appeared as an ingredient in a couple of the dishes – and was very pleasantly surprised by its texture and flavour!

Driving to London on the Friday, I could not pass up the opportunity to visit Farmoor Reservoir, particularly as there were a couple of grey phalaropes – a species that I’d not seen before. The weather was grim but seeing them was easy because they remained at the edge of the smaller northern lake. They had arrived about three weeks previously but  disappeared the next day, so I felt particularly fortunate.


The two juvenile grey phalaropes at Farmoor Reservoir were easy to find, but difficult to photograph as they moved so fast and the water was choppy.

Getting engaged to Jennifer

Last Saturday, I got engaged to the awesomely wonderful Jennifer Siggers! Here are a few photos that mark the occasion.

Getting engaged at Hampton Court Palace

Getting engaged at Hampton Court Palace

Jen had been keen to show me Hampton Court Palace. I thought that the venue had some potential for asking her, so I checked the website and soon saw that the Privy Garden had plenty of cosy nooks. When we arrived there, I was horrified to find that the trees there were no more than two foot high, and the whole garden was consequently very exposed… Shedding any pretensions to being cool, calm and collected, we then went in search of a more suitable location, and found an arbour that was just right.

Marking the occasion at Hampton Court Palace

Marking the occasion at Hampton Court Palace



Shortly after we first connected, it was obvious that our relationship could really develop. Jen is a lecturer in bioengineering in London, having originally studied maths – so we do occasionally have geeky conversations about science!  She’s also a regular at All Souls Langham Place (where John Stott was rector for many years) – so we’ve also been known to discuss theology…

Aunty Jen with George, only a couple of days old... photo by Andrew Siggers

Aunty Jen with George, only a couple of days old… photo by Andrew Siggers

I’ve greatly enjoyed being welcomed in by Jen’s family – which has included the privilege of meeting her nephew when he was only a few hours old! He was born on New Year’s Eve, and as I was driving Jen back home the following day, we ended up visiting Andrew (her brother) and Rachael less than a day after all the drama.

Jen and I have a shared love of wild places, which is fortunate as on an early date I asked her to crawl through a hedge. (This was near the Ullenwood long barrow – I hadn’t worked out where the field exits were!). Later I took her up into a howling gale in the Peak District. We agreed the walk would have been lovely on a hot summer’s day.

Ring-necked parakeet in the grounds of Hampton Court Palace.

Ring-necked parakeet in the grounds of Hampton Court Palace.

I have tried very hard not to indoctrinate Jen into the world of birdwatching, but in a bizarre but true twist I had a life tick within minutes of our getting engaged, at the very same spot! Ring-necked parakeets are unknown in Worcestershire, but very common in this part of Surrey. Indeed, later in the evening there were several small flocks of them flying around fast and squawking noisily.

The first two photos were taken by a couple of folk who happened to wander past at the right moment – and they were both really excited to be involved in marking the occasion!

Around the beginning of November we were both really wondering whether we would ever meet ‘the right person’: I could scarcely have believed that I was about to meet such a stunningly amazing lady as Jen, and it is even more incredible for us now to be able to begin to plan life together.

Remembering Gheluvelt

In October 1914, a few miles east of Ypres, about 350 men from the Worcestershire regiment changed the course of World War One. It’s an extraordinary story of courage and bravery under extreme pressure.

I heard about it for the first time last week during a service in Alfrick: a part of the intercessions was given over to remembering the centenary of the battle for Gheluvelt, which had happened a couple of days previously.

The memorial at Gheluvelt Park in Worcester

The memorial at Gheluvelt Park in Worcester

As I understand it, there are very few occasions in military history where the actions of one small unit can make a major difference to the direction of an entire war – but this was one of those occasions.

Towards the end of October 1914, the British army was in deep trouble – they were massively outnumbered by a rampant German army. On the 31st, the fall of the strategic locality of Gheluvelt to the Germans meant there was little to stop the Germans driving the British army back to the French ports, probably out of the country as well, and achieving a quick win.

At this point desperate measures were needed and the 2nd battalion of the Worcestershire regiment was the only one left in reserve. At 2pm, three divisions were sent into action, crossing open ground that was littered with dead and wounded British soldiers, and under constant bombardment from the Germans.

This counter-attack took the Germans completely by surprise, and they retreated fast. What the Worcestershire regiment did not know was that the Gheluvelt chateau was still being held by the South Wales borderers: but this meant that they were able to combine with them and successfully retake Gheluvelt.

The battle at Gheluvelt Chateau, by J.P.Beadle: the Worcestershire battalion meet the South Wales borderers.

The battle at Gheluvelt Chateau, by J.P.Beadle: the Worcestershire battalion meet the South Wales borderers. (Painting from here)

It is curious that the Germans did not re-group and re-take Gheluvelt – they may have vastly over-estimated the remaining strength of the British army. The upshot of it is that they lost the opportunity to break through the British lines and achieve a quick and complete victory in the war. Instead, the British were able to make a short, tactical retreat to a stronger position, and consolidate their lines – which would be there for the next four years.

Poppy crosses to some of those who had fallen at Gheluvelt

Poppy crosses to some of those who had fallen at Gheluvelt

Shortly after arriving in Worcestershire I had noticed a park in the north of Worcester which had the odd name of Gheluvelt. I now understood why! I visited it yesterday to pay my respects. As the centenary of the battle was a few days ago, there were poppy crosses to some of those who had fallen. One was to a ‘Great Uncle Alfred Farmer’; another was for 8513 Albert Perks, and read ‘A very proud grandson. A Grandad I never met’. He had been a clay miner hewer from the Stourbridge before the war, and fell at Gheluvelt. His great-grandson Matthew Perks has added a comment below, which I highly recommend reading.

The story of Gheluvelt is extraordinary and inspirational: yet it came at a heavy cost to those involved. There were 370 men who took part – of whom just over half (187) were killed. The park and its memorial is a fitting tribute to those who fell both in that battle and at other times during the war.

The full story is told here.

Entrenched in Martley

One of the new trenches at Martley Rock

A couple of weeks ago, I found myself avidly staring into a freshly-dug, multi-coloured trench. It was one of several located in a recently-harvested farmer’s field west of Martley.

The site – known as Martley Rock – has an extraordinarily diverse range of geology located within a small area. Rarely can one find rock from such a variety of ages within such close proximity: in a short stretch, there’s half a billion years’ worth of geological history represented by five different bands of rock!

In the image here, the bands in the trench are, from bottom to top:

  • Bromsgrove Sandstone from the Triassic (240 million years ago);
  • A narrow band of Raglan Mudstone, which has a slightly pinker tinge, and is from the Silurian (420 million years ago);
  • The greyish band is from the Halesowen Formation, which is mudstone and clay from the Carboniferous (310 million years ago);
  • The Malverns Complex from the PreCambrian (about 700 million years ago – that is, substantially before advanced life-forms appeared on Earth), which is the dominant rock type in the Malvern Hills;
  • The pale whitish-yellow band at the top is Malvern quartzite from the Cambrian era (520 million years ago).

At this point the trench goes left and downhill.

One of the reasons for the complexity here is that there are two dominant fault-lines running through the site: one is the East Malverns fault, which runs roughly north-south and then down along the eastern side of the Malverns; the other is the much shorter Martley Rock fault. In both cases, major crustal movements have brought together rock types that were formed over a hundred million years apart (the Triassic sandstone and the Silurian mudstone, and the two Malvern rock types).

However, there are also other important geological boundaries represented here: in the trench shown, there’s an obvious one on the near side of the grey band. The Raglan mudstone from about 420 million years ago is the narrow strip of pinkish-brown rock, which would have been formed when England was about 20 degrees south of the equator: the Martley area was probably covered by a shallow sea. Next to it is the grey-green Halesowen formation from about 310 million years ago, when the area was probably a low-lying river delta system, with dense forests of ferns on land: this also gave rise to the coal beds further north. Both eras were times when rock was predominantly being formed; in between was an era in which erosion was the more important process, which is why there is such a large time gap between the two rock layers. (See here for a fuller description of some of the geology on the site)

Spoil heaps by one of the trenches

Even the spoil heaps are dramatically colourful!

John Nicklin – the secretary of the Teme Valley Geological Society – flew a radio-controlled helicopter over the site and took some spectacular photos, including the one below. The different rock types are clear not just in the spoil heaps by the trenches but also in the changing soil colour as well.

Aerial view of the new trenches at Martley rock. The different rock types are clear not just in the spoil heaps by the trenches but also in the changing soil colour as well. At top left is Berrow Hill.

Aerial view of the new trenches at Martley rock. At top left is Berrow Hill. Photo by John Nicklin of the Teme Valley Geological Society.

The story of strontium

An explosive start, a volcanic interlude, a learned Scottish cleric, an English genius, and a couple of Bronze Age skeletons.

An updated version of this story can be found here.

It was the road sign that got me intrigued: “Strontian: the village that gave its name to the element Strontium”. This is a village in Ardnamurchan with just a few hundred people: although it has both a post office and secondary school, which helps to make it a focal point for a wider area, it’s not even close to being a small town. And yet it has this unusual claim to scientific fame.

Strontian: "the village that gave it's name to the element Strontium"

The road sign approaching Strontian

This set me on a trail, as I wanted to know how the element came to be specifically there in the first place – and how it was recognised to be a new element as opposed to another previously known one. I have found it a fascinating quest – but telling the tale requires starting at the beginning, because – as all astronomers know – without the stars there would be no strontium in the first place…

An explosive birth

Supernova in the nearby galaxy M95. It's only during these events that elements heavier than iron - like gold, lead or strontium - are formed.

Supernova in the nearby galaxy M95 (circled). It’s only during these events that elements heavier than iron – like gold, lead or strontium – are formed. Image from here.

The story starts about five billion years ago, in the glowing gases of the nebula out of which the Sun would eventually be formed. It is likely that the critical event was a supernova explosion: this is when a massive star, many times the size of the Sun, blows up. All of the naturally occurring elements which are heavier than iron are formed only within the spectacularly intense heat of a supernova explosion – and then scattered far and wide into the surrounding nebula of glowing gas. Strontium is one of the elements that would have formed. By sending shock waves through the nebula, the explosion may also have been the trigger that led to the formation of the Sun and other stars.

However, much as this might explain how strontium got formed, I still wanted to know how it ended up specifically on the Ardnamurchan peninsula.

When Scotland flowed with volcanic lava

The key era was around 400 million years ago, which geologists term the ‘Devonian’: it was a time when trilobites scuttled along the ocean floor; giant ferns dominated the land; and the earliest insects began to appear.

Scotland was a very different place: it was located south of the equator, attached to what is now Scandinavia, and was volcanically active. During this era, the Caledonian mountains were built up, which would have looked much more alpine than they do now.

One of the multitudinous events that took place then was that a crack appeared in the Earth’s crust near where Strontian is presently located. Into it seeped searingly-hot molten magma from the Earth’s mantle. There’s nothing geologically unusual about this – except for its part in this tale.

The centre of the photo shows the Whitesmith mine near Strontian, right on the long but narrow rock seam formed about 400m years ago (the Devonoan era). Image by David McCallum from

The centre of the photo shows the Whitesmith mine near Strontian, right on the long but narrow rock seam formed about 400m years ago (the Devonian era). Image by David McCallum from here.

When hot molten magma cools, different elements solidify at different temperatures: they will either sink within the cooling magma, or stick to the walls of the crack. Strontium has a melting point of 769K, but in its molecular form, strontium carbonate (which became known as ‘strontianite’), it solidifies at 1050K. Other elements like lead or tin, which solidify at much lower temperatures, rise to the top.

The Caledonian mountains have long since ceased being volcanic. Instead, a much more recent process has been important: the Ice Ages had a dramatic effect, with glaciation eroding the mountains down until what remains now are just the cores of the old, Alpine-like ranges.

Searching for minerals in the wilds

In the early eighteenth century, the first glimmerings of the Industrial Revolution were appearing. Thomas Newcomen had pioneered the first steam engine – but it would be another fifty years before James Watt’s historic improvements. Ardnamurchan – a peninsula south-west of Fort William which was easier to reach by boat than by land – was reputed to be a wild and lawless place, but it had geological riches that promised much for mineral speculators.

In the hills above Strontian, a strip of rock was discovered from which lead ore could be extracted. In 1729 a Royal Charter was obtained to work the mines, but over the following years the mines had a long, turbulent and unproductive history: there was never enough lead ore, or any other economically important mineral, to turn a regular profit; the management was usually ineffective. Moreover, the owner had miners imported from northern England which exacerbated conflict with the Highlanders. In 1760 the mines experienced the first of several closures, and became derelict for a time.

Liechtenstein stamp from 1994 featuring Strontianite.

Liechtenstein stamp from 1994 featuring Strontianite.

Four years later, the Rev John Walker, a minister from Moffat, was asked by a group of three organisations, including his employers the Church of Scotland, to visit the western Highlands, to assess their ‘moral and physical condition’. Walker was not a gifted pastor, but he was already developing a reputation as a brilliant scientist, achieving prominence in the nascent fields of botany, geology and chemistry. He would later become Professor of Natural History at Edinburgh, achieving an international reputation, and inspiring hundreds of students from many countries.

This trip in 1764, the first of several over the following years, enabled him to combine his work with his hobbies. His report on the economy of the area was thorough, articulating both the need and potential for developments in agriculture and education – but the tour also gave him the chance to continue to build up his growing collection of mineral specimens. When he visited the Whitesmith mine above Strontian, his skills meant he was uniquely equipped to be able to recognise the new mineral that would later be called strontianite. His own chemical analysis convinced him that it contained ‘a new earth’, but it would require others to establish that this was indeed the case.

An elementary genius

The eighteenth century was a time when the science of chemistry was beginning to develop as an academic discipline. In particular it was believed that different minerals might be composed of basic elements, each element conveying distinct properties to the whole. A key task therefore was to be able to identify and isolate these elements. The first breakthrough was the separation of oxygen by Joseph Priestley in 1774.

It was some time before Walker’s new mineral could be adequately analysed. For a while, it was thought to be the same as another mineral from the north Pennines, called witherite, which was visually very similar. On this basis a sample was analysed by an Irish physician called Adair Crawford. He was a meticulous scientist, particularly known for his work on animal heat. In 1790 he established that the mineral from Strontian – which he named strontianite – was distinct from witherite. He deduced that there was probably a different chemical element involved.

Doing a flame test distinguishes clearly between the strontium (red) and the barium (yellowish green). Original images here.

Around the same time, Thomas Hope – a former student of John Walker – was doing a more thorough chemical analysis, to give a much clearer indication of what the ‘new earth’ might be. He found that the strontianite and witherite were virtually identical in their chemical reactions, but that the strontianite was about 15% lighter. A more marked distinction was that strontianite burned with a bright red colour, whereas the witherite burned with a faint greenish hue.

What neither scientist was able to do, though, was to separate either of the two earths from the rest of the minerals in which they were found. This was achieved later by the man who did so much to develop and shape the early science of chemistry – Humphrey Davy.

Sir Humphrey Davy

Sir Humphrey Davy by John Linnell.
UK Government Art Collection 2010, licensed under the Open Government Licence.

Davy was a brilliant experimental scientist who acquired celebrity status because of his gift for dramatic presentations of his scientific discoveries. He was particularly well known for his invention of a safe miner’s lamp, but he also developed the technique of electrolysis, which was a major breakthrough in chemistry.

Davy’s insight was that the newly discovered phenomenon of electricity might have something to do with the way elements combine and therefore how chemicals form. His conviction was that electrolysis could therefore be used to separate these elements.

By 1808, he had already used this technique to identify several new elements, such as sodium, calcium and potassium. However, extracting the elements from witherite and strontianite proved difficult. He tried various methods to induce the elements to separate – finding, for example, that combining each of the minerals with ‘red oxide of mercury’ facilitated the process. However, once they formed, they reacted quickly with the oxygen in the air, and violently when in water, reverting back to their original state: sulphuric acid was a better medium. Eventually he was able to produce a metallic sample in sulphuric acid, which sank without reacting. Once he accomplished this, he recognised the need to name the new elements: that from strontianite became strontium, and that from witherite was called barium.

Deciphering the Bronze Age

The underlying reason why strontianite had been confused with witherite was that the key elements of each mineral (strontium and barium respectively) are chemically very similar. They are now known to belong to a group of elements, along with calcium, magnesium and radium, in which each behave in a like manner.

This product utilises the chemical similarities between calcium and strontium - whether it is effective, I have no idea.

This product utilises the chemical similarities between calcium and strontium – whether it is effective, I have no idea.

Thus, if strontium is absorbed into the human body, it is processed as if it were calcium: in human bones there is one strontium atom to every 1500 calcium atoms. This is the key to its technological usage: its similarity to calcium means that it is not a lucrative mineral to mine, but it does have medical and archaeological benefits. For example, strontium-enriched bones seem to be stronger than normal bones, which provides a method of treatment for those with bone diseases such as cancer.

Like the other 94 naturally occurring elements,  strontium is defined by the number of protons in its nucleus: in this case, 38 protons. However, there are different varieties (or isotopes) of strontium, defined by the numbers of neutrons in their nuclei: for example, the most abundant of these is called strontium-88, because it has 50 neutrons in addition to its 38 protons.

The four varieties that are found in nature are all stable. However, there is another version, strontium-90, which is a product of nuclear weapons testing – and is itself highly radioactive, decaying with a half-life of 29 years. As it is easily absorbed into the human body, it is a major reason for the incidence of bone cancer in regions with significant nuclear fallout.

The different varieties of strontium come in varying proportions, depending on location. This is reflected in the bones and teeth of both humans and animals, which absorb the strontium irrespective of the variety. This therefore provides archaeologists with an important tool, because bones and teeth from ancient human skeletons can be analysed to find out where they originated.

Archaeologists have used strontium analysis on Bronze Age skeletons found near Stonehenge to show just how mobile people were at that time.

Archaeologists have used strontium analysis on Bronze Age skeletons found near Stonehenge to show just how mobile people were at that time.

This is dramatically illustrated by two that were found within a few miles of Stonehenge. For example, there was a teenage boy with an amber necklace, buried 3,500 years ago – the unusual ornament indicating a high rank. Analysis of his teeth showed that he originated from the Mediterranean. Another skeleton, from 4,300 years ago, hailed from the Alpine foothills of Germany. This shows just how mobile people were in the early Bronze age – and that Stonehenge was probably significant to people across Europe, and not just within Britain.

The almost-uniqueness of Strontian

Strontianite on display in the Tourist Information Centre at Strontian

Strontianite on display in the Tourist Information Centre at Strontian

On the Swedish island of Rosaro, there is a village called Ytterby. At a nearby mine, the mineral yttria was discovered from which no fewer than four elements were discovered, between 1794 and 1878: yttrium, ytterbium, terbium and erbium. This is the only other settlement which has had a naturally occurring element named after it. (Germany, after which germanium is named, is a country, not a settlement!) Strontian’s distinction, while not quite unique, is nevertheless sufficiently unusual that it is surprising that not more is made of it. Even in the village itself it deserves a bit more acknowledgement than a road sign: strontium may not be a well-known element, but its story would certainly grace a museum in Strontian!

Quirky archives

It’s strange what you find when you go through your old photos… as I found when I decided to get my photo collection in order. Here are a few ‘gems’…

First is a rare selfie… taken behind closed doors, in a bathroom… and I never told the owners, nor anybody else for that matter. It’s time to come clean.

The bathroom had a nice row of mirror tiles that went on both sides, so the geek in me wanted both to count the reflections and then photograph them.

What the guest did in the bathroom.

What the guest did in the bathroom.

I found that to get a good photo I needed to sacrifice the number of recorded reflections – and also realised that if I grinned at the camera, the result looked naff. So I didn’t. I must admit that one of my first thoughts on re-discovering this image from four years ago was , ‘much less grey hair in those days’!

Deep... very deep...

Deep… very deep…

A couple years later, while working in Cheltenham and doing the photographic project on the River Chelt during lunchtimes, I chanced upon a kid’s toy by the side of a road. I thought this had some potential, which could therefore reveal an artistic side to my photography. When I downloaded the images later, searching for something ‘deep’ in the photos, I realised that one message came out far louder than all the others clamouring for attention: “this is a kid’s toy found by the side of a road”.

Finally, I was reminded of the most educated graffitti I’ve ever seen, carefully laid out in stones on Leckhampton Hill, in the quarry workings between the Devil’s Chimney and the summit, about ten years ago.

Leckhampton Hill: date of manufacture

Leckhampton Hill: date of manufacture

Apart from the mock precision, the statement is reasonably accurate – but not one that would be known without at least some acquaintance with geology! The Cotswolds were formed in warm, shallow seas in the Jurassic era, in similar conditions to the Bahamas today – although probably ‘only’ 170 million years ago. (There’s a good summary of the geology here.)