The Astronomical Slates at Bryn Twrw

Bryn Twrw, Tregarth

This is a superb set of three of the largest slates recorded, dated 1837, from Bryn Twrw, Tregarth.  While they share the charecteristic features (date, names ot owners etc.) of other carved slates, they are otherwise different.  There is a purpose behind the decoration and the carving takes up the entire surface area on all three slates.  They were still in position around the fire and have been blackleaded for 145 years so that they look like black satin. 

Interpretive drawing by Jeremy Yates of the Zodiac carved on the central panel of the Bryn Twrw fireplace.

They are carved in minute and perfect detail incorporating the comparative sizes of the plantes and their orbits, explanations of exlipses and comets and a highly original representation of the Zodiac in which Virgo is running as fast as she can to escape from Leo whi is in hot pursuit!  Two salmon swim in water poured for them by Aquarius, and Taurus is charging the twins.  The lanuage used for all the complex astronomical explanations on the slate is in Welsh.

The Eclipse of 1836 and Halley's Comet

Research into this one discovery has led to a wealth of information about the source of this astronomical data found in a small farmhouse kitchen.  The source was John William Thomas (Arfonwyson) 1805-40, a mathematical genius born at Rallt, Pentir, not far away.  After three years of schooling and seven in the quarry he had educated himself sufficiently to become a teacher, and kept school at various places including Blaenau Ffestiniog and Tregarth.  He wrote a number of books – Elements of Mathematics, a Welsh Dictionary of Technical  and Scientific Terms, a Grammar, An Infalliable Way for a monoglot Welshman to read English correctly (which involved the early use of phonetics) and some Almanacs.  His book on Astronomy, which was nearing completion when he died, has been lost with the exception of the first few paragraphs which are in beautifully clear and vivid Welsh.  He went to London and became Private Secretary to William Cobbett, M.P.  After Cobbett’s death a letter from Arfonwyson to a London friend, containing a drawing explaining Halley’s Comet and the Eclipse of 1836 (pictured on the slate), brought him to the attention of the Astronomer Royal.  After a stiff examination by three Professors of Astronomy he was appointed to the staff of Grenwich Observatory where he soon became Supervisor.  He was in charge of planning the work of the Observatory when he died at the age of 35.  Sir George Airey refers to him as ‘my computer, Thomas’.  He had kept close contact with his friends in Dyffryn Ogwen, advising some of them on the study of the Tides, the Moon and the Atmosphere.

His gift of astronomical patterns and information to Richard and Grace Jones of Bryn Twrw was translated into slate carving of great detail and perfection by her brothers, Thomas 1808-1840 and William 1815-1855.  They produced an outstanding work of art, yet all that is known of them is that they were ‘Quarrymen and Farmers’ of Bryn Twrw.  The waelth of talent associated with the small group of houses at Bryn Twrw is only recalled in the fragmented and contradictory references.   These slates are their only memorial, but a worthy one.

Click on a thumbnail in the gallery of photographs below to see further information about each slate where this has been added. The image number refers to the record number in the database of carved slates.


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