Date Made/Found: 1840-1890
Material and Medium: electroplated Britannia metal, white metal
Dimensions: Overall: 160 x 160 x 285mm (6 5/16 x 6 5/16 x 11 1/4in.)
Department: Decorative Art
Accession Number: 2007.45
This teapot was made by John Harrison of Sheffield between 1840 and 1890.
On the bottom of the teapot is the maker's name 'HARRISON NORFOLK WORKS SHEFFIELD'. Also stamped on the base are the pattern number (1204) and the number five, which gives the capacity of the teapot in half pints. The letters 'EPBM' indicate that the teapot is made from electroplated Britannia metal, which is an alloy (a mixture of different metals) very similar in composition to pewter. Like nickel silver, it can be electroplated to give an appearance close to solid silver.
The teapot is illustrated in a catalogue of Harrison's goods. It was part of a set with a matching coffee pot, sugar basin and a milk or cream jug. Both the teapot and coffee pot have distinctive bird shaped finials (knobs) on their lids. The set is very ornate in its shape and decoration. Although the style of the teapot does not appeal to most people's taste today, it would have been very fashionable in the late 1800s.
John Harrison manufactured a range of goods for the home. These included a range of tea and coffee services, flatware and cutlery. An original pattern book tells us that Harrison made dessert knives with blades made from close plate (a form of silver plating on iron). He used the marks 'I H S' alongside 'PS' on these items.
Harrison's pattern book reveals that he made some impressive pieces of tableware that must have been very expensive. These included elaborate epergnes for serving fruit and displaying flowers, candelabra, glass decanters with stands, and cruet frames with cut glass condiment bottles.
Hidden History: what is it made from?
In order to discover what metals were used in the Britannia metal alloy, we took the teapot to Sheffield Analytical Services to be tested. Unfortunately, the teapot was too large to fit into the testing machine, so we unscrewed the bird finial so that it could be tested.
Hidden History: what do Sheffield Analytical Services do?
Sheffield Analytical Services are part of Sheffield Assay Office. They are responsible for the testing of products for purity. This is known as assaying. Objects made from gold, silver and platinum must be assayed before they are hallmarked.
Hidden History: how was the teapot finial tested?
The finial was tested using a technique called X-Ray Fluorescence (XRF). This is a non-destructive method, meaning that the objects were in danger of being marked or damaged in any way. The tests were carried out for us by Matthew Hawker, who is Team Leader in the XRF Sampling Department.
Hidden History: what is XRF?
XRF is a surface analysis technique used by Sheffield Analytical Services to test items for purity before they are hallmarked.
Hidden History: how are XRF tests carried out?
An x-ray is fired at the sample which penetrates the top layer to a depth of 0.01 - 0.1 mm beneath the surface. The material then itself generates x-ray radiation that varies according to its composition.
The fact that the x-ray penetrates the surface means that the composition of the both the surface and underlying metal can be analysed. This is very useful if an object has been electroplated or gilded, giving it the appearance of solid silver or gold. The test will reveal the composition of the plate and the underlying metal.
If there is any ambiguity in the test results, the surface of an item can be scraped to remove the layer of plate. The object can then be retested to determine if is made from a solid precious metal or not. Obviously, surface scraping was not carried out on objects from the collection, as this would create permanent damage.
Hidden History: what did the test reveal?
The finial was found to be made from an alloy of silver (49%) and tin (50%). In order to be eligible for hallmarking, a silver item must have a minimum purity of 92.5%. This is known as the Sterling standard. Traces of gold were also detected (0.9%). This suggests that the finial might have once have been gilt.
Find out more…
Discover more objects made by John Harrison in his original pattern book held at the Local Studies Library, which is in Central Library on Surrey Street:
'Patterns of Silver, Nickel Silver and Electroplate…' (reference number 739.07 SQ).
Images from this pattern book have been reproduced with the kind permission of Sheffield Local Studies Library.