Purveyor of Bollocks to the Crowned Heads of Europe
Monday, 17 October 2016
Geology, architecture and fantasy
A grotto fountain at the Georgian house which is home to the American Museum.
That cascade of rock which hovers above the now empty bowl of the fountain is Tufa - the same stuff as I have just imported 2 tons of from Canada, via Ohio. The trouble is we are not allowed to dig our own up any longer, despite the fact that it replaces itself every few years.
Oh well, I suppose it makes sense. Everyone would want their own little Tufa grotto here in England if dealers were allowed to retail it. The stuff I got is to replace the missing parts of an 18th century structure - probably stolen by 20th century gardeners...
The main structure of the arch is made from stuff called 'Grot Stone', and this was dug up about 3 miles away on the other side of the valley, in a little wooded hamlet called Conkwell, where I once lived in a picturesque cottage next door to the last Governor of Hong Kong. Shawn lived about a mile or two from here when she first arrived in Bath.
This stone (it is a true stone, unlike Tufa) is characteristically riddled with worm-like holes of varying diameter, and the artificial architectural masonry representation of it is called 'Vermiculated' stonework - more references to worms. It is invariably used for the lower courses of grand buildings, such as the outside of the Roman Baths here.
Nobody is too sure about how these tunnel holes were formed - some say it was marine-life burrows, and others say it was the action of water-courses. It is also a rare commodity these days, second-hand stuff selling for around £1000 a ton, and it only takes a cubic yard to make a ton.
When you saw up Tufa - it is very soft and easiy sawn - it gives off a highly pungent and sulphurous odour which is quite unpleasant. This is due to all the organic matter which has left fresh gas trapped within it, released by the saw-cuts.
The same is true of some real stones which are 140 million years older than Tufa, and I like the theory that this gas is the trapped farts of dinosaurs when wallowing in the mud which formed the rock. Why not? There is such a thing as 'copralite' - look it up.
There is one particular type of Bath Stone which has smallish lumps of ferrous metal embedded in it which shine brightly when the saw cuts through the rusty exterior.
Scientists tell you that this metal is formed by the minerals grouping together over the millions of years, resulting in concentrations of metals and crystals, but I prefer the theory of one particular stonemason I knew once.
He assured me that these lumps of iron are the remains of alien space ships which crashed into the primordial mud of earth's watery surface during the era of the dinosaurs.
As I say, life is so much more interesting when you are prepared to believe in anything.