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Showing posts from February, 2013

Westgarth Forster 1821: "Cauk, or barytic, spar"

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One of the treasured crystallized minerals from the mines of Northern England is the barium sulphate barite (or baryte). Beautiful doubly-terminated 6 cm blue barite from Frizington, Cumbria, with red areas resulting from hematite inclusions. Westgarth Forster (1821, pages 216-217), makes the following comments on this mineral: “ Cauk , or barytic , spar, is not generally of so pure a white as the calcareous spars. The writer of this has seen cauk spar of a dead white, but commonly it is of a yellowish, a brownish, or a reddish white, or of a flesh colour, sometimes crystallized and transparent, as at Dufton-fell , in the county of Westmorland. It seems to affect the peculiarity of having its crystals laminated, as radiating from a centre, but this radiation seldom amounts to a whole circle. It is commonly a dull ill-looking spar, frequently rising in in globes and irregular masses, and so exceedingly heavy, that miners have always imagined it contained metal

Westgarth Forster, 1821: "Fluor spar occurs in veins in a great many different colours"

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Reading through  Westgarth Forster's 1821, “A Treatise on a Section of the Strata from Newcastle to Cross Fell”, I came across the following (on page 218): “Most of the mineral spars are frequently found shot into prismatic, cubic, hexagonal, or other figures. These figured crystals are generally transparent, and very beautiful. It is a great curiosity to behold the inside of some of the large cavities in which they are formed. These caverns, lined with crystals, are frequently met with in hard mineral veins; and they are generally called, by miners, shakes , lochs , or loch-holes .” On page 216 he writes the following about one of these mineral spars (today known as fluorite): “Fluor spar occurs in veins in a great many different colours, viz. white, green, violet, yellow, red, and brown. Its most general form, when crystallized, is a cube, but it is frequently met with in the form of an octahedron and cubo octahedron, it also occurs in amorphous shapeles

Carboniferous Geology in Roundhay Park

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Remembering my old running, cycling, tree-climbing haunt of Roundhay Park (North Leeds) today I thought I'd show some pictures related to the geology of the place. Firstly here's a GoogleEarth view of the northern end of Waterloo Lake, with "The Folly" at the top of the grassy slope and "The Gorge" snaking away beneath the sea of trees. And here below is a sketch map I made about a decade ago for a guided tour. The tour started at the outlet of the upper lake (1), went past the folly (at 2) then along the West side of the gorge before descending to the stream and continuing back down the gorge (3 and 4) towards Waterloo Lake. You'll see there's a fault, shown in red, where the gorge meets Waterloo Lake, with Elland Flags to the South and Rough Rock with Millstone Grit mudstones to the North. The vertical order of the different rock types is shown in the following sketch: Looking back at the sketch map you'll see that the yo

Jan and Cora Gordon: Guitars in Spain

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As a youth I would hear stories about Jan Gordon and his guitars, for example one about a border crossing at which the customs officer charged duty on a cheap new guitar and nothing on an old and valuable instrument. The story deepened for me on reading " Poor Folk in Spain " and " Misadventures with a Donkey in Spain "; and then even further, in the summer of 2009 , when we followed in the footsteps of Jan and Cora Gordon with their donkey, Colonel Geraldine, on the second of their Spanish journeys. Both Jan and Cora  made some fine paintings, drawings and etchings during and after this journey, such as this one by Cora and this by Jan (the favourite picture of "Telephones" on their return to London in 1931). Perhaps my favourite of their Spanish works is the etching shown below. Paco, the chief of police, plays guitar at José’s in Puerto Lumbreras.  The wonderful thing about this picture is how well it illustrates the narrat

Jan Gordon, 1927: "Shocks in Modern Art Used Up"

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Amongst the many journeys of Jan and Cora Gordon was one that crossed the USA. I found this entertaining small article today, dating from that trip, in the Pittsburgh Post Gazette for December 4th, 1927. "Shocks in Modern Art Used Up, Painter Says": "Modern impressionistic art, according to Gordon, who watched the whole movement at close range in Paris, has little to offer of startling nature. Not for a century or so, anyway." I somehow think that there may have been quite a number of shocked reactions to some of the art made during the 85 years that followed these words. Jan Gordon published a book on " Modern French Painters " in 1923. He had tried out the text on my grandparents as the book was being written and dedicated the volume to them. The "hospitable roof" mentioned in the dedication was "Mesylls", painted here by Jan Gordon over Christmas in 1918. The journey during which the Pittsburgh article was written

Jan Gordon: Dazzle Camouflage in Nature and War

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Following their Serbian adventure in the early part of the First World War,  Jan and Cora Gordon returned to London, with Jan then working for the Royal Naval Reserve . Reading about the work of  Jan Gordon  and others during 1917 and 1918 on ship camouflage during the war, I remembered our pet cuttlefish Ramses. Ramses ( Sepia pharaonis ) showed remarkable abilities to change colour patterns and textures in order to blend with surroundings as can be seen in a series of videos and photos here . Note in particular the " motion dazzle " patterns used when escaping a perceived threat, and more analogous to the dazzle patterns developed by Norman Wilkinson, Jan Gordon and others during WW1 (see below). It was also a joy to watch these creatures in the wild in warm Omani waters . Ramses is impersonating a patch of sand Wild relatives in Marjan Bay. There is more communication than camouflage going on here. This is the same couple as shown above.