What emerges from the records is that the main purchasers of these salts were local manufacturing chemists. Some purchasers are only names for whom no details have been traced. All those who can be identified are either manufacturing chemists, or in closely related trades. The minute books, although often obscurely written, reveal a wide range of other transactions - these include enquiries, sales, tenders and barter deals. The type of transaction, taken together with the customer, and what can be found about them, is really all the evidence that there is.
Only two customers can be identified who bought all three salts. One of these was a major manufacturing chemist, the other, not so easy to identify, was probably a leather manufacturer.
Richard Farmer's vitriol factory was founded in 1778 on Kennington Common. Later St.Agnes Place covered the area. His son, Thomas, who was commemorated by Thomas Road (now gone), succeeded him, in Kennington. In 1839 Farmer became the first industrial chemist to use pyrites on a large scale as part of the process for sulphuric acid manufacture. Thomas Farmer held an 1840 patent for the process.6 The company dealt with the early Chartered providing 'sulphuric and muriatic' acids in barter arrangements for coke. They also provided other chemicals and took all three salts from the Chartered in a variety of arrangements.
'Learmouth' was the other company that bought all three salts. They were either a drysalter or, perhaps more likely, the large Bermondsey tanning company - the two directory entries could, in any case, refer to branches of the same business. They bought salts over a period of only eighteen months in 1832‑3 ‑ but, of course, could have been one of the regular customers, records of whose transactions have not survived.
Farmer clearly dealt in a very wide range of chemicals and it is no surprise that they should have bought an equally large range, perhaps to be sold on elsewhere. Learmouth, as a drysalter, would have sold chemicals and, equally, had a need of a wide range.
If the Learmouth of the minute books was in fact the leather merchant then the purchase of this range of salts is particularly relevant. A clue to this is can be found in Winsor's pamphlets, written thirty years earlier. He had suggested that ammoniacal liquor could be used by tanners and made a claim that it was 'one of the strongest lyes for tanning skin, cheaper and quicker and superior than what can be done by bark'. In the traditional tanning process, skins were treated with lime and dung, and then steeped in a solution of oak bark. Research was then in progress on many aspects of tanning and ammonia compounds were among the substances, thought likely to be useful.