Sunday 19 April 2015

Working Portland Stone

Easton, Bath and Portland Stone Firms, Ltd., Portland. General view of mason's workshop in Portland Stone works. Works of Bath and Portland Stone Firms, Ltd. 1930.
BGS Image ID: P023985
Easton, Bath and Portland Stone Firms, Ltd., Portland. General view of mason's workshop in Portland Stone works. Works of Bath and Portland Stone Firms, Ltd. 1930.

Easton Quarry, Isle of Portland, Dorset. There are several quarries in the Easton area working the white freestone limestones known as Portland Stone. In the early 19th century, when many of the quarries were still in the hands of the Crown, they were principally worked by convict labour. Large stone columns are a feature of most classical stone buildings and in later times many British architects copied such classical themes. Portland Stone proved to be ideal for this purpose because the beds of limestone are quite thick. Here a section of stone column is being turned on lathe at the works of the Bath & Portland Stone Company. The section is of 4 ft. diameter, and is one of five constituting a column 25 ft. high. As Portland Stone seems to be less affected by pollution than other United Kingdom limestones it has been widely used in London, particularly since the early 19th century e.g. Custom House, St. Paul's Cathedral, The Bank of England, Whitehall and Downing Street.
BGS Image ID: P204941
Easton Quarry, Isle of Portland, Dorset. There are several quarries in the Easton area working the white freestone limestones known as Portland Stone. In the early 19th century, when many of the quarries were still in the hands of the Crown, they were principally worked by convict labour. Large stone columns are a feature of most classical stone buildings and in later times many British architects copied such classical themes. Portland Stone proved to be ideal for this purpose because the beds of limestone are quite thick. Here a section of stone column is being turned on lathe at the works of the Bath & Portland Stone Company. The section is of 4 ft. diameter, and is one of five constituting a column 25 ft. high. As Portland Stone seems to be less affected by pollution than other United Kingdom limestones it has been widely used in London, particularly since the early 19th century e.g. Custom House, St. Paul's Cathedral, The Bank of England, Whitehall and Downing Street.

Easton, Bath and Portland Stone Firms, Ltd., Portland. Hand-carving in Portland Stone. Only straightforward work such as that on ashlar and on mouldings is carried out by machine. Finer work is all done by hand. Works of Bath and Portland Stone Firms, Ltd.
BGS Image ID: P204947
Easton, Bath and Portland Stone Firms, Ltd., Portland. Hand-carving in Portland Stone. Only straightforward work such as that on ashlar and on mouldings is carried out by machine. Finer work is all done by hand. Works of Bath and Portland Stone Firms, Ltd.

Easton, Bath and Portland Stone Firms, Ltd., Portland. Travelling crane lifting block of masonry in Portland Stone. Works of Bath and Portland Stone Firms, Ltd.
BGS Image ID: P204950
Easton, Bath and Portland Stone Firms, Ltd., Portland. Travelling crane lifting block of masonry in Portland Stone. Works of Bath and Portland Stone Firms, Ltd.

Easton, Bath and Portland Stone Firms, Ltd., Portland. Stack of finished masonry in Portland Stone. The diameter of sections of fluted columns in foreground is 4 ft. Works of Bath and Portland Stone Firms, Ltd.
BGS Image ID: P204951
Easton, Bath and Portland Stone Firms, Ltd., Portland. Stack of finished masonry in Portland Stone. The diameter of sections of fluted columns in foreground is 4 ft. Works of Bath and Portland Stone Firms, Ltd.

 Posted by Bob McIntosh
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Monday 6 April 2015

China-clay works, Devon and Cornwall

Lantern China-clay Works, near Rescorla, St. Austell. Looking SW. View of lower part of clay-pit. This photograph, taken down in the pit, shows the stream of water, by which the clay is washed out of the decomposed granite travelling down the stope and from thence through the sand-pits to the 'bottom hole launder', whence it is pumped to the surface. The sand-pits are only partly visible in the photograph, but the annexed diagram shows the direction of flow of the water.
BGS Image ID: P200171
Lantern China-clay Works, near Rescorla, St. Austell. Looking SW. View of lower part of clay-pit. This photograph, taken down in the pit, shows the stream of water, by which the clay is washed out of the decomposed granite travelling down the stope and from thence through the sand-pits to the 'bottom hole launder', whence it is pumped to the surface. The sand-pits are only partly visible in the photograph, but the annexed diagram shows the direction of flow of the water.

Hendra Downs China-clay Works, St. Dennis. Looking N. Team and waggon with load of clay.
BGS Image ID: P200203

Hendra Downs China-clay Works, St. Dennis. Looking N. Team and waggon with load of clay.
China clay workings, Great Pit, Lee Moor, south Dartmoor. General view of china clay-pit showing systems for disposal of waste sand; (1) right, old inclined railway to large 'burrow', and (2) left, new covered conveyor belt to small burrow (sited on ground having low clay yield). China clay is formed by the kaolinization of granite, a process of late hydrothermal alteration where acid solutions moved along the joints in the granite and caused the plagioclase feldspars to be converted to kaolinite. The name kaolin comes from the mountain Kauling in China where the material was discovered. Large scale exploitation began in the 18th century. Recently the industry has become intensively mechanized.
BGS Image ID: P2009710
Old photograph number: A09799   1962
China clay workings, Great Pit, Lee Moor, south Dartmoor. General view of china clay-pit showing systems for disposal of waste sand; (1) right, old inclined railway to large 'burrow', and (2) left, new covered conveyor belt to small burrow (sited on ground having low clay yield). China clay is formed by the kaolinization of granite, a process of late hydrothermal alteration where acid solutions moved along the joints in the granite and caused the plagioclase feldspars to be converted to kaolinite. The name kaolin comes from the mountain Kauling in China where the material was discovered. Large scale exploitation began in the 18th century. Recently the industry has become intensively mechanized.

Posted by Bob McIntosh
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