Croll remained, however predominately a chemical manufacturer. The Alum and Ammonia Company had been set up in the mid-1860s taking over from a predecessor Gas Products Utilising Company. Croll said that the company had works in Hurlet - a tiny hamlet near Paisley - and in West Street Glasgow, buying liquor from Glasgow Gas Works, and also at Nine Elms in London. It certainly had a works on Bow Common, where, in 1859, Croll was prosecuted for nuisance.
This site appears to have been on the north bank of the Limehouse Cut, west of Poplar North Street. It can be deduced that sulphuric acid was made there because, as Croll reported to a shareholders' meeting, 'the floor of the vitriol chamber had given way' and 'a crowbar had been forced into the lid of the large vitriol chamber'. In addition the 'secretary had falsified the accounts' and 'there was an action for libel against him'. The shareholders wanted Croll to resign on this occasion but he refused. He also refused to publish the company accounts, claiming 'commercial confidentiality'.
The Alum and Ammonia Company made 'ammoniacal alum'. 'Alum' is another chemical with a changing definition. It is a modern everyday name for 'a hydrated double salt of aluminium and potassium'; a modern chemist means 'a class of salts that crystallise with twenty-four molecules of water'. Its ancient use meant 'astringent salts'. Alum had been used since the middle ages as a mordant for fixing colours in dyeing and for 'tawing' leather. The manufacture of alum is tied to that of copperas but it is also made on the Yorkshire coast where a local aluminous shale was used as a raw material. In the 1790s Charles Mackintosh had begun the manufacture of alum from the waste of coal workings around Hurlet.50 Frederick Albert Winsor might have known of this process when he said, in 1804, that ammoniacal liquor could be used to make alum.
The development of a successful process for ammoniacal alum has been ascribed to Peter Spence who, in 1834, came to London and researched the use of waste lime from the gas works. Later, finding the process unsuccessful, Spence left Limehouse and went north to research alum and copperas. He set up a works in the Manchester area to make alum using ammoniacal liquor from the gas works, patenting the process in 1845.
There is no obvious sign of Spence in the gas company minute books. The nearest source of gas lime for him would have been the East London Company's Wapping works at Prusom's Island (a few minutes away by barge). There are no minute books for the East London Gas Company so he cannot be traced through them. Spence is said to have worked at Henry Street, Commercial Road - an address on the Limehouse Cut, which could roughly be described as being on Bow Common. Henry Street is today's Stainsby Place, a turning from Stainsby Road going the distance of the depth of a suburban house to works backing onto the Limehouse Cut. It is difficult to believe it was big enough to ever have many buildings in it. In the 1870s the East London Saltpetre Warehouse was at the end of it. It would have been roughly opposite Croll's works, on the other side of the Cut - but more of that later.
Ammoniacal alum was being investigated elsewhere in the area. In 1851, a James Wilson of Stratford registered a patent. James Thompson Wilson was not the same as James Pillans Wilson then managing Price's Candles. There is however a connection between this London company and alum. Prices had been set up by William Wilson, of the Scottish ironworking family. John Wilson, Lanarkshire ironmaster, alum manufacturer, ex-partner of Charles Mackintosh and father in law of Charles Tennant, obtained the entire liquor production of Tradeston & Partick gasworks in 1851 - another tangle of relationships between these industrialists.
Previously alum had been imported into London. One importer was Thomas Farncombe, Chairman of South Met. Gas Co. in the 1840s. Farncombe is described as 'Agent to the Boulby Alum Works' at Freshfield Wharf. Boulby, on the Cleveland coast, was a 'traditional' alum works dating from 1650, and closed around 1870.
By the 1870s Croll was not the only manufacturer. Both Frank Hills and Bethel were making alum at East Greenwich Works. At Old Ford Ellis was also active in this field. Why were these works in London? Farncombe' imports may have been destined for the Bermondsey leather industry; where Croll, as we have seen, had contacts. Some alum might have gone to the growing paper industry in the east end of London and in north Kent. A number of paper mills were started in this period in Bow and Bromley by Bow. Alum was used as a size to make paper more water-resistant. A third destination might be the cement industry now growing in London and north Kent. A number of new processes in cement manufacture used alum.