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Sunday, 9 August 2009

Ammonia salts

Once again the names of things become confusing. ‘Sal ammoniac’ became better known as 'ammonium chloride’. It was also once known as 'muriate of ammonia’ - 'muriate' once being the term which defined a chloride. All three names are used, apparently at random, in the gas company minute books in the early nineteenth century. It could be made by adding hydrochloric acid to the ammoniacal liquor.

In advertising the proposed gas company in 1809 the projectors had mentioned, in particular "the manufacture of muriate of ammonia’. Accum's evidence on this to the 1809 Enquiry had been the source of extensive criticisms by Henry Brougham, acting for Boulton and Watt. Brougham questioned the methods used to make the sal ammoniac in tests set up for the Enquiry. He had pointed out that "no one denied" its usefulness and reminded the Enquiry that sal ammoniac had been made for many centuries. Dundonald made it as a by‑product of tar manufacture.

Brougham was right, of course. There had been a number of sal ammoniac manufacturers in Whitechapel and Bermondsey in the late eighteenth century, perhaps supplying the growing paper industry, like Koops' Neckinger paper mill. Sal ammoniac was used in medicine, by dyers and by tin plate workers. There were a number of these in London - like John and Thomas Bore, tin plate workers of Commercial Road who were subscribers to the scheme to light Mile End Road and perhaps hoped for cheap supplies.

Before the gas industry came along sal ammoniac was the best known ammonia salt, and there was one other in common use. This other principal ammonia salt, which Accum had advertised before 1810, was ‘sal volatile’ or ‘ammonium carbonate’ sometimes, commonly, called 'smelling salts' or ‘carbonate of ammonia’ ‑ once again the early nineteenth century gas industry used all four terms indiscriminately. This particular salt was one which Accum had claimed could be made and sold for ‘16 guineas a hundred weight".

With Accum's words in mind the Chartered's Court of Governors commissioned experiments on ammonia salts as well as on the use of the liquor itself. Another Chartered Director, Benjamin Newton, a notary arranged these, in May 1814. Strangely however, the brief for the work appeared to be for something completely different to either sal ammoniac or sal volatile. Newton commissioned a Mr. McCormack to undertake tests on liquor. These were to be 'one without addition and one with addition of oil of vitriol'. A fortnight later McCormack was paid off and no results were noted. There the matter seems to have rested for two years.

In 1816 a David Richards did another set of tests. Soon after Clegg recommended to the Board that ‘sulphate of ammonia be made with the surplus liquor’. 'Sulphate of ammonia' had no common name, and is always known by the more modern idiom of 'sulphate of..' rather than 'sal'. It was a salt which Accum had hardly mentioned in his lists of chemicals which could be profitably made from gas industry wastes. It was however the beginning of a new and enduring manufacturing venture.

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