Neglected Bradford Industries: Copperas

Bradford is famous for spinning and weaving but textile production was only one of a group of important industries which ‘Worstedopolis’ supported. Since several  are now almost forgotten by contemporary citizens I should like to draw attention to those which seem unreasonably neglected, in a series of short articles.

  I would be delighted if any reader has ever heard of copperas, let alone that it had once been produced close to the city of Bradford.  Copperas is nothing whatever to do with the element copper, but is an old name for ‘green vitriol’ or iron II sulphate heptahydrate. Copperas was used in the manufacture of iron gall ink, leather tanning, and a very early process for the production of sulphuric acid. Copperas, like alum, was also important as a mordant in cloth dyeing processes. For centuries both these chemicals were papal monopolies. The monopoly was eventually broken and in the early post-medieval period the production of alum, on the North Yorkshire coast, and copperas, at several sites round the country, marked the origin of the domestic chemical industry. The industry flourished and the UK became the world’s biggest copperas producer.

At various times production works existed in several places, this being indicated by name evidence: Copperas Hill in Liverpool, Copperas Road in Colchester, Copperas Point in Chichester Harbour, Copperas House Terrace in Todmorden, and Copperas Bay on the Stour estuary in Essex. The technique adopted  was similar at the various sites. Some years ago I was surprised to learn from historian Jean Brown, of the Thornton Antiquarian Society, that Denhome had been a centre of this industry. From trade directory evidence it is clear that, between 1822-1854, copperas was being made at not only there but at Hunslet, Birstall, Huddersfield, Elland, Southowram and Todmoden as well as in the cities of Manchester and Liverpool. Nineteenth century historian William Cudworth, writing about Denholme, recorded that an extensive coal seam was then being worked by Messrs. Townend of Cullingworth and that in parts of this Hard Bed coal ‘quantities of iron pyrites were to be found’. Cudworth stated that the process of converting iron pyrites, or pyrite, into sulphuric acid was carried on along the line of the coal seam’s outcrop. He omitted to say that two copperas works, Field Head and Denholme Gate, were associated with a family called Horsfall.


08 Plan Image

Essentially the Copperas process was the slow oxidation of iron (II) sulphide, obtained as the mineral pyrite, using atmospheric oxygen and rain water to form iron (II) sulphate heptahydrate, that is copperas. Essential to the process was, of course, access to a plentiful supply of pyrite. Pyrite nodules (‘brass lumps’) are found in the Coal Measures in Cumbria and West Yorkshire. At Denholme the producers obtained the nodules and placed them in ‘beds’ lined with clay. They were then left to weather for up to six years. Towards the end of this time they began to produce a large quantity of liquor, a dilute solution of hydrated ferrous sulphate and sulphuric acid, which was pumped into a lead boiler positioned over a furnace. Quantities of additional scrap iron were added to increase the final yield. As the liquor was reduced by evaporation more liquor was added. When it was  sufficiently concentrated the liquor was tapped off into a cooling tank. As the solution cooled the copperas crystallised in the tank. Crystals were collected, heated to melting point, and poured into moulds; finally the resulting cakes were packed into barrels for transport.

Why did the industry survive in Denholme? The most important property of copperas for nineteenth century textile manufacturers in Bradford must have been that it ‘saddened’ and ‘fixed’ wool dyes. Because it prevented the colour from washing out or fading, copperas became an essential part of the black dyeing process, especially for woollen cloth in conjunction with log-wood imported from South America. We known that cheap coal and pyrite nodules could be obtained with minimum transport costs and I imagine that once the plant had been set up there were little additional capital costs.

The cheap manufacture of vitriol, in Bradford and elsewhere, by the lead chamber process inevitably killed off the copperas industry. Once you can make sulphuric acid cheaply and in bulk you can make copperas more quickly by reacting the dilute sulphuric acid with scrap iron fragments and evaporating the result. The discovery, by Sir William Henry Perkin in 1856, of aniline dyes which did not require mordants were to make copperas largely redundant in dyeing in any case. Elsewhere copperas works were adapted to produce other industrial chemicals but this did not happen at Denholme in its rather rural location. Nevertheless at one time this community was a small but significant centre of Britain’s chemical industry. By 1888, at the very latest, all production had ceased.

If this topic interests you do read the following paper which includes Jean Brown’s meticulous family history studies:

D.J.Barker & Jean K Brown, Bradford’s Forgotten Industry: Copperas Manufacture in Denholme, Bradford Antiquary, (2015) 3rd series, 19, 25-38.

Derek Barker, Local Studies Library Volunteer.


In the basement of Bradford’s Local Studies Library are collections of nineteenth century pamphlets (and some of earlier date). Ranging from sermons and programmes of royal visits, to reports, articles, obituaries and regulations, they are a treasure-trove of local history. What follows is an account of one of these treasures. To consult any of these items please ask the staff. Card catalogues of these collections are located in the Local Studies Library.

 JND 290/13 (Please quote this number if requesting to this pamphlet.)

 The Paris Universal Exhibition, 1878. Report of Henry Mitchell.


 In Treasures Of The Week Number 1, we featured an account of Sir Henry Mitchell and reported that in 1878 he was Vice-President of the jurors selected to adjudicate upon worsted yarns and fabrics at the Paris Exhibition of 1878. The report he made of that Exhibition influenced in the establishment of the Bradford Technical College. The 13th item in Pamphlet Volume Number 290 of the J N Dickons Collection is a copy of that Report. The full title is:

The Paris Universal Exhibition, 1878. Report of Henry Mitchell, Vice-President of the Jurors appointed to adjudicate upon Worsted Yarns and Fibres; (President of the Bradford Chamber of Commerce, President of the Bradford Technical School, etc.) together with the Reports of the Artisans and others who were sent out to report on the textile fabrics, products and machinery engaged in the Worsted Trade, and on some of the French Technical Schools.

The Report is 73 pages long and was printed by William Byles and Son of Bradford.

In addition to Mitchell’s extensive Introduction, the other contributors were:

  • Thomas R. Ashenhurst, Head Master of the Bradford Technical School (‘French Technical Schools’);
  • William Bottomley of Saltaire (‘Report on the Worsted Fabrics’);
  • Mitchell Stead, Weaving Overlooker (‘Report on the French Technical Schools and the Exhibition’);
  • A Spinning Overlooker (‘Report on the Exhibition and the French Technical Schools’)
  • Peter Greenwood, Spinning Overlooker (‘The Worsted Yarns and Machines, and the Technical Schools’);
  • James Speed, (‘Worsted Yarns, Machines, and the French Technical Schools’);
  • William Deighton and Z. Hoyle, (‘Report on the Exhibition Generally’);
  • James Newsome, Overlooker, Saltaire (‘Report on the French Textiles and Machinery’);
  • John Dufton, Pattern Dyer, Messrs E. Ripley & Son, Bowling Dye Works (‘Report on the Dyed Fabrics’);
  • Jonas Whitley, Wool Merchant, Bradford (‘Report on the Wools in the Paris Exhibition’).

Even without going into detail, we can see from the many reports by experienced textile workers, including Mitchell himself, how seriously the exhibition was taken, and how much attention was paid to technical education.

Mitchell was knighted in 1885 for his services to textile education and now has a building named after him. But his fellow reporters are now probably forgotten, except here!

Sir Henry’s report was received with much attention by the commercial world, and there is no doubt the practical suggestions and conclusions there laid down have yielded very useful results. (Quote from JND 290/4)

A particularly interesting slice of history in the making.

Stackmole (Local Studies Volunteer)

Treasure of the Week #1 – Sir Henry Mitchell

In the basement of Bradford’s Local Studies Library are collections of nineteenth century pamphlets (and some of earlier date). Ranging from sermons and programmes of royal visits, to reports, articles, obituaries and regulations, they are a treasure-trove of local history. What follows is an account of one of these treasures. To consult any of these items please ask the staff. Card catalogues of these collections are located in the Local Studies Library.

 JND 290/4 (Please quote this number if requesting this item.)

Sir Henry Mitchell of Bradford – A Biography. c.1880. 8 pages


Sir Henry Mitchell

The fourth of the seventeen pamphlets bound together in volume number 290 of the J N Dickons Collection is a slim eight-page account, plus portrait, of Sir Henry Mitchell of Bradford. The pages are taken from a book of which neither title, nor author, nor publisher, nor date (1880s?) is noted. Two other biographies accompany Mitchell on JND 290 from the same anonymous source. One is on The Worshipful Mayor of Bradford, Mr Angus Holden, and the other is on Lawrence Game, a prominent lawyer and MP for East Leeds (number 3 and 5).

Opposite the Local Studies Library at the bottom of the Manchester Road is Sir Henry Mitchell House, currently the base of some of Bradford Council’s staff, but few people know who Sir Henry Mitchell was, or did. But in the book store in the depths of Margaret Macmillan Tower, is the answer. Although brief, the account is concise and fact-filled, lucid and fulsome.

Henry was born in 1824 at Esholt and aged fourteen he commenced learning the different processes of wool sorting, combing, spinning and weaving. In 1842 he was  appointed Manager for Messrs William Fison & Co., of Bradford, of which  W E Forster, M.P. was a partner. 1848 finds Mitchell as a Buyer for Messrs A & S Henry & Co. of Bradford, becoming a partner in 1852. In the next few years Mitchell becomes a leading figure in the commercial life of Bradford. He was elected a member of Bradford Town Council in 1870 and was a councillor for 21 years, being made an Alderman in 1874. He was also an influential and active member of the Bradford Chamber of Commerce, being elected President on four occasions. In 1876 he was the English Judge for woollen and silk fabrics at the Philadelphia Centennial Exhibition. Two years later he was Vice-president of the jurors selected to adjudicate upon worsted yarns and fabrics at the Paris Exhibition of 1878.

Education as well as textiles was a passion in Mitchell’s life. He was a member of the first School Board elected for Bradford, Vice-President of the Bradford Mechanics’ Institute, and a Governor of Bradford Grammar School. But his greatest work was in connection with the Bradford Technical College.

‘He saw clearly that if England was to retain her supremacy in the production of worsted fabrics, it was necessary that a higher and more systematic training should be adopted on the part of those whose lot it would be to carry the trade forward in the face of foreign competition; and he set his heart upon the establishment of a Technical College in Bradford which should at least equal anything of the kind attempted abroad.

The College was erected at a cost of £40,000, of which Sir Henry subscribed £10,000. The College was opened by The Prince of Wales in June 1882, with Mitchell appointed President. He was made an Honorary Member of the Worshipful Company of Clothworkers in honour of his work in promoting textile education, and a member of the Board of Governors of the City and Guilds of London Institute.

Respected by workers and employers alike, Mitchell was employed to arbitrate in trade disputes, notably in the great dyers’ strike. He was chairman of the local Conservative Party, but resisted frequent attempts to persuade him to stand for Parliament. He was a prominent member of the Wesleyan Church in Bradford. He was knighted in 1885 and made a Freeman of the Borough in 1889, the year of his death.