The difference a week makes.

A week ago we had our hottest walk on Dartmoor with clear blue skies and panoramic views. Yesterday it was so, so different! Back to normal really for Cornish weather. We started off by taking a public bus from Callington to Pensilva (hooray for the free bus pass) and then walked back on lanes and footpaths. A wet and misty day for a 7 mile walk but enjoyable nonetheless.

The view at the start of the walk and it didn't really get any
better as we progressed.

Very green and very wet lanes.

More water - horizontal rather than vertical this time. Along the
River Lynher below Golberdon.

A soggy lunch on a soggy day.

Lots of cow parsley in the hedgerows.



The view at the end of the walk. Plus ca change!

A little mining history

Just to remind us that the ground
was contaminated with arsenic.

A trip last night across the River Tamar into Devon to take part in a guided walking tour organised by our local history group. On a lovely sunny evening, we visited the site of the Devon Great Consols (DGC) which was, in fact, a consolidation of five adjacent mines which were worked for copper and arsenic in the nineteenth and early twentieth centuries. At its peak, DGC employed around 1,300 people. The mines were named mostly after the shareholders or their wives – Wheal Maria, Wheal Fanny, Wheal Anna-Maria, Wheal Josiah and Wheal Emma. The site is huge and covers almost 70 hectares but we walked around a mere fraction of this area.


Our guide, Rick, waxing lyrical
about a hole in the ground. I'm sure he'll agree
that this was his natural habitat! 

DGC was in operation from 1844 until 1900 and then again from 1915 to 1930. Copper was extracted first and in total over 750,000 tons of copper ore were recovered. In 1850, the site was regarded as the richest copper mine in Europe. Copper reserves started to run out around 1870 and, luckily for all concerned, demand for arsenic increased almost simultaneously due to its use in the dyeing, paint and glass industries as well as a pesticide in the cotton fields of the USA. Unlike copper, large amounts of arsenic were refined on site using the ‘calcination’ process and in total yielded 72,000 tons of product. In the 1870s half the world’s arsenic production was estimated to have come from half a dozen mines in the Callington and Tavistock area, including DGC.

A grinding wheel that seemed to lend itself to
B/W rather than colour.

Most mining activity on the site ceased in 1902. However, in 1915 the upper levels of Wheal Fanny were reopened for the extraction of arsenic ore. A price slump in 1925 occurred mainly due to the introduction of non-arsenic based pesticides and this led to the suspension of activity and final closure followed in 1930. The last recorded industrial activity on the site dates from the early 1970s when a milling plant was installed to recover tin from the mine waste. However, this operation proved to be short-lived due to the decline in the tin price a few years later

Part of the arsenic processing area, with baffles for the sublimation of the arsenical gases in the foreground and the chimney for the release of the sulphurous fumes in the background.

DGC is now a site for tourism and recreation through the Tamar Valley Mining Heritage Project and forms part of the UNESCO World Heritage Site for the mining landscape of Cornwall and Devon. The site is now crisscrossed by recreation trails that are well used by cyclists, walkers, mountain bikers and horse-riders. And did I mention the views?


Looking west-ish across the site with some Duke of Bedford's miners' cottages in the distance. Hard to imagine that 150 years ago that this would have been a hive of industrial activity with many water wheels and steam engines in operation.

South-ish for this view, looking straight down the river valley. In the woods in the background is a local view point - Chimney Rock. Well worth the hike there for the panorama over the valley.

A day in the life...............June 23rd 2014

A nice gentle day with my IWC today. A walk around the garden first thing, followed by a Pilates session, a quick bit of shopping in Tavistock and then it was off to the Elephant's Nest pub at Horndon for a lunch in the sun. And, as we were so close to the moor, we had a walk! Hooray for the joys of being retired.

Our hostas are starting to come into flower. Another week or so and they'll all be out.

Ditto our Echeveria elegans, also known as Mexican snow ball and Mexican gem. Mmm, I wonder where it originates?

Any objective person would say that we don't really get a lot of early summer colour in our garden so it's always good to take pleasure when we have some.

Black elder or Sambucus nigra. I think this variety is called Black Lace. We bought it from the Duchy of Cornwall Nursery but I doubt if Prince Charles got his hands dirty raising it.

We were planning to walk from Willsworthy, a place well into the moor. But the red firing flags were up, meaning 'Do not walk within the marked posts as army firing practice is going on'. And it was because we could hear the crackle of small arms fire in the distance. The firing range has been here since early Victorian times and the army is still one of the biggest landowners on Dartmoor.

 

We did walk as far as we could, taking the route along the side of an old mine leat built around 1800. You can just about make out a red warning flag on top of Ger Tor in the background. Incidentally, transgression means getting shouted at by a burly man with a gun. I know as it happened to me once. Needless to say, I beat a hasty retreat. Self preservation is very high on my list of attainments.

As we couldn't walk where we had planned, we took another route nearby. Great clear skies again and some wonderful panoramas. This one is vaguely due north looking towards Widgery Tor, about 10 miles away as the bullet flies.

 

Strange things seen in the hedgerows Part XXV: a sealed plastic vial containing a slightly viscous pale yellow fluid. My guess is that it's an injection ampoule of some veterinary product. And, given all of the cow-related paraphernalia in the vicinity, I think it was destined for one of them.

A slightly out-of-focus pied wagtail methinks. So what's interesting about this not-uncommon bird? Not a lot but I'm still pleased with what my new 35-105 mm lens can do. Without it, the subject was just a twitching dot on a distant rock.

Dontcha just love foxgloves? As I said in an earlier blog, it's been a very good year for them.

I call this one 'Insect on blue flower'.

This one I call 'Two insects on one blue flower'.

A babbling brook - and that's enough babbling from me for one day.

 

Our hottest walk on Dartmoor?

Phew - what a scorcher! And hot it certainly was for this month's walk with our regular group. It makes sense, doesn't it? One of the hottest days of the year and we head for the open moor where there's no shade. It wasn't that bad in reality and the clear conditions gave us some long-reaching views over the moorland and down to the sea at Plymouth Sound.

As for last month, we started at Norsworthy Bridge at the top of Burrator Reservoir but this time we headed south east up the Deanscombe Valley. Once there we followed the stream through the old tin workings to the mine at Eylsebarrow. From there our route took us over the hill to Nun's Cross and then it was cross country to Down Tor and back to our starting point. My GPS clocked just under 6.5 miles which, under such conditions, was probably far enough for one day.

Lots of clouds at the start but these soon disappeared, leaving mostly clear blue skies.

For a few hundred yards we had some shade but it didn't last as we moved onto.......



...the open moor. Here we are looking back towards our starting point with Peek Hill, Leather Tor and Sharpitor in the distance.




What's this? A double line of stones going up a hill? Actually, these mark the position of the flat rods that used to take the power from the large water wheel down the hill to the tin-ore processing machinery at the top. The stones themselves were the guides between which the flat rods went back and forth. Not very mechanically efficient but effective given the terrain and resources available at the time (circa 1830).

A vista looking north east over Fox Tor Mire, reputedly the setting for Grimpen Mire in Conan Doyle's 'Hound of the Baskervilles'. The view stretches for some 25 miles.

"Cotton grass grows where you shouldn't go" or so the saying goes. Not a problem for this patch but a warning that should be generally heeded.

Ah, that's what this Bronze Age stone was originally placed for.

Stone row dating from 2000-3000 BC. This one is not far off a kilometre in length and has a stone cairn at one end, which is just about visible in the distance.

And a stone circle with standing stone at the other. No-one really knows the purpose of such structures, of which there are many on Dartmoor. The consensus seems to be settled on something ceremonial or religious.

However, this cow obviously has an alternative theory - they were originally scratching posts for Bronze Age cattle. It works for me!

The view from the top of Down Tor looking west to Burrator Reservoir.

And at the end of the walk, a welcome ice-cream by the reservoir. I think we'd all earned one by this stage.

The lady wants church flowers: the lady gets church flowers.

 "I want more pictures of church flowers", she said. "Your wish is my command", I said. It's only through the internet that a Welshman in Cornwall can swiftly (sort of) accede to a request from Iceland made by a native of Wisconsin but long-time resident of North Carolina. And it's a pleasure so to do.

The theme for the event was 'Colours of the Rainbow'. Can't remember what they are? Think 'Richard Of York Gave Battle In Vain'. Oh yes: red, orange, yellow, green, blue, indigo and violet. Here are the welcoming swathes either side of the original 13th Century church door. Those familiar with this area will be saying "where's the notice board?". I've photoshopped it out as it detracted from the blooms.

And what's at the end of a rainbow? A pot of gold, that's what. And you can see that on the bottom right.

Given that the displays were part of the Village Fair celebrating the 175 years that our Village Post Office has been in existence, a sub-theme for the flowers was picking out the colours of old postage stamps. Here, a one penny Queen Victoria stamp sets the scene..............

..and here a green 1/2d stamp from Edward VIII's reign.

This array takes its colour from a pictorial stamp of a butterfly from the present Queen's time.

Not sure about the stamp that inspired these colours as it wasn't around at the time I was there.

An Edward VII orangey red stamp was the basis for this window.

Another with an unknown stamp association. I really should pay more attention to these details.

Here's the Queen Victoria blue stamp inspired display in its entirety. I should add that all of the flowers and greenery were grown within 5 miles of the church.

Are floral displays greater than the sum of their parts?

It depends on the flowers, I think.

Pigs 'Ere Blog Part 9: some interesting facts about Sus Scrofa

When I were a lad I quite often worked, part time and for a pittance, on various farms round and about our village and it was then that I first fell in love with pigs. And it was reciprocated too, in a sort of way – largely contingent on me presenting myself regularly bearing armfuls of potato peelings and such like and leaning over the pigsty wall to do a little ear tickling. To this day pigs remain a love of my life and, given my scientific background, perhaps readers will be unsurprised when I find a convergence of the two too irresistible not to mention. Stay with me with some porcine science.

A friend (thank you, KS) has pointed me in the direction of a publication** in which the genome sequence of a female domestic pig, together with those of some of her relatives, has been described. Before we get on to why you less love-struck unfortunates should give a grunt about this, I must make it clear that no animals were harmed in unveiling this sequence. Rather, a small piece of an ear or a few teaspoons of blood were enough to grow cells from which DNA was distributed to the many research groups involved.

So what did the members of the Swine Genome Sequencing Consortium (what a lovely name) give us as the result of their labours? Well some things you would have guessed anyway: pigs have about as much DNA in their cells as we do (about 3,000 million base pairs). Of course they do: they’d have to be pretty similar for folk like me to go round falling in love with them. And within that sequence they have more genes (over 1300) encoding smell receptors than any other animal  – which obviously helps if you have to root around in the woods for a bite to eat before becoming reliant on admirers bringing edible gifts. Of course, there must be a downside to being so olfactorily endowed but that's their problem. I wonder what they make of my macho aftershave?

Meishan Pigs

But what about the differences? Well, close though I feel to them, pigs and humans last had a common ancestor about 90 million years ago and a domesticated pig first trotted out of South East Asia about 4 million years ago. Separate strains of the domestic pig then evolved in Western Europe and East Asia and these diverged from the various strains of wild boar – though the separation is somewhat murky due to pigs being prone to roam, a habit that led to what is delicately called ‘genetic mixing.’ So beauties like our Lops turn out to be more closely related to European wild boars (Oh dear, better not offer any of our meat to UKIP supporters) than they are to Chinese pigs such as the Meishan.

One of the things that happened as pigs went their separate evolutionary way is that their DNA became unusually prone to being broken. Although damaged DNA is usually repaired, two consequences tend to arise. Sometimes a gene just gets lost and this has happened with quite a few that we originally shared with pigs that enable us to taste things like salt: by losing that sensitivity pigs have acquired the ability to eat things we can’t. The other result is that pigs are quite good at shuffling bits of DNA to make novel genes (and hence proteins) – something called alternative splicing if you are interested. But perhaps the most important outcome is that pig DNA has acquired about 100 changes (mutations) that in humans are linked to increased risk of things like Alzheimer’s disease and diabetes. Pigs have a long and noble history as good models for human disease and we use their heart valves in replacement surgery (how’s that for reciprocated love?). Having a peek at their DNA has revealed that they also offer a natural model to find out what happens in some of our worst afflictions.

Pigs: giving us their hearts, sorting out our frailties – and making more roast dinners than you can shake a trotter at. Everyone should love ‘em!

** Groenen, M.A.M. et al., (2012). Analyses of pig genomes provide insight into porcine demography and evolution. Nature 491, 393-398.