SW8243 : Calenick Crucibles

taken 8 years ago, near to Kea, Cornwall, Great Britain

Calenick Crucibles
Calenick Crucibles
With the introduction of the reverberating furnace LinkExternal link (Archive LinkExternal link ) for smelting tin at the turn of the 18th century it became common practice to assay the black tin (tin ore or cassiterite) prior to smelting. This involved a carefully weighed quantity of black tin being mixed with a small amount of anthracite dust, put into a crucible and heated in a furnace to approximately 1400 degrees centigrade and held at that temperature for 20 to 30 minutes. The crucibles (also called melting pots) were, at that time, imported and quite a number failed in the intense heat. In the middle of the 18th century a reward was offered to anyone who could produce crucibles of suitable quality using British materials, after several attempts a formula was perfected using “china stone” which appears to be a rough form of china clay. It is worth noting that this was around the same period as when William Cookworthy discovered that hard porcelain could be made from china clay (kaolin).

Using this formula, Calenick Crucible Company was established in about 1770 and continued until 1900 when production came to an end due death of James Jamesª who became owner sometime in the late 19th century. For reasons, only known to her self his widow, Charity, had all the records and other paperwork relating to the works destroyed.

The image above shows a collection of crucibles that has been found, by my members of my family, at Calenick, over a period of over fifty years. The crucibles at each end of the top row are, as far as can be established, the approximate colour of the originals. The others are very heavily stained having been in the river bed or river mud for a hundred years or more.

Crucibles were sold in various sizes fitting together in sets, or nests, as shown in the centre of the bottom row. The two on the left of the bottom row are the same size as the middle two but shown side by side. It is not known at this time how many made up a nest but fragments of much larger than the ones shown have been found

In an advertisement in the West Briton of 3rd March 1815 crucibles were offered for sale by the Calenick Crucible Company at two shillings and nine pence per dozen nests. About £0.14

The position on the map is the approximate sit of the works.

ªNot my relation
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SW8243, 50 images   (more nearby )
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Date Taken
Sunday, 6 June, 2010   (more nearby)
Monday, 21 June, 2010
Industrial heritage > Industrial heritage   (more nearby)
Subject Location
OSGB36: geotagged! SW 8200 4324 [10m precision]
WGS84: 50:14.9303N 5:3.5506W
Camera Location
OSGB36: geotagged! SW 8200 4324
View Direction
NORTH (about 0 degrees)
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