The most telling point made by Lowe to the Oil Gas Enquiry was his account of the considerable efforts made by the coal gas companies to clean the gas before it was supplied to customers. One of the processes, new in 1826 was 'dry lime'. This also led to problems of refuse disposal although some experiments were carried out on its use as an agricultural fertiliser. Gas companies were sometimes approached with requests such as 'a barge load of refuse gas lime for ... a farmer at Southall' and this subject was intermittently discussed in detail over the next years. It was, however, said that if the lime was not used as a fertiliser it could, alternatively, be a weed killer.
Since this is not a history of gas purification, but of waste products, a discussion of the various developments in the purification process is not really relevant - interesting as they were. For a while, however, purification became a battle ground for warring manufacturing chemists.