Throughout the 1840s and early 1850s the gas companies were besieged by manufacturing chemists with variations on these purifying schemes all complaining about numerous patent infringements, both before and after 1849. Chemists visited the gas companies, threatened legal action and offered deals. Some examples have been given above. The visits, the threats and the offers went on for more than twenty years. It is hard to believe that the gas company directors were not confused. The potential profits to Croll, Laming and Hills must have been enormous.
After 1849 the gas companies began to prefer to use the oxide process which Laming had demonstrated at the Westminster Gas Works. Frank Hills ruthlessly insisted that this was his patent. Any gas company that wanted to use it had to have a licence from him to do so. If they did not have his licence, he simply sued them. A sequence from the South Met. Minute Books demonstrates his methods. In February 1852 Frank Hills approached South Met. and asked for £400 a year for permission to use his method of purification. Following discussions with them he raised the price to £425. Laming then approached them with an offer of a licence for £400 a year and so the South Met. Directors chose the Laming offer. Three weeks later Hills complained to them that his patent was being infringed and said that South Met. must have a guarantee of no claims from him. In June South Met they received a letter from Frank Hills' solicitor, Shield and Co., 'about inclination to take action for infringement of his patent'. In July they agreed to pay Hills what he wanted.
The financial arrangements for the use of the purification process were usually complicated and subject to much haggling. Gas companies were sometimes supplied with the purifying mixture to put in their machines for which they had to pay per ton of coal carbonised. For example, in 1853 Laming asked the Chartered, who had been paying 4 1/2d. per ton, to pay 5 1/2d. and to back date this rise three months. The Company agreed 'provided the Company now be provided with the purifying material they require'. Laming did not supply the material until he had received this back dated sum.
The chemical manufacturers removed the spent oxide when it could no longer be revivified and took to be used in their chemical works. Frank Hills processed vast amounts at his Deptford and Greenwich works. He himself designed the furnace in which this was done. Lunge estimated that 2,180 tons of spent oxide were used a year at a works at Barking Creek to make sulphuric acid. This works at Barking was probably Lawes Creekmouth works, which had opened in 1857. Lunge's comment therefore refers to amounts used after that date. In addition ammonia and sulphur were recovered from the mixture, giving more sources of profit to the chemists.
In the later 1850s a series of legal actions were started. Some were between the chemists and the gas companies others between individual manufacturing chemists. In 1858 in Frank Hills v. the London Gas Company, a battery of lawyers heard a series of complicated statements on patent law and chemistry - 'arguments which were almost certainly beyond the understanding of the jury, and, one suspects, of counsel and judge as well'. Deliberate clouding of the details probably suited all parties very well. In one case, which involved an agreement between Hills and Laming and claims for 'liquidated damages', the judge commented that the matters were 'monstrously absurd.'
Frank Hills finally established his right to the patent. Rev. Bowditch commented that this was what 'the majority of lawyers and chemists think he was most justly entitled to'.
Exasperation on the part of the gas companies is reflected in the minute books. On one occasion his conditions on ammoniacal liquor included special conditions should the canal freeze. Underlining in the minute book clearly indicate the Chartered Directors' attitude.
The gas companies began to get together about the situation. They circulated information to each other - 'a letter was read from the directors of other companies with information at some degree of variance with statements made by Mr. Hills before this Court' reported the Chartered Company. As the time drew nearer for his 1849 patent to expire, Frank Hills announced that he was going to apply for an extension of it. He began to include in his contracts with the gas companies a condition that the gas companies would not oppose his application for an extension - for example he offered Chartered the process at 5d. per ton provided that they do not oppose an extension.
Eventually an appeal from a consortium of gas companies went to the Privy Council. Thomas Livesey, Secretary of South Met. Board reported to them 'he [Frank Hills] had received £107377 0s. 9d. for sales and royalties. His expenses rated £16,942 only, but his other expenses included £6,450 for his own salary after paying the same sum to his brother, Thomas, and some large sums to some other brothers....'77. As a comparison, it should be noted that Thomas Livesey, a well respected and well paid manager, received a salary as South Met's engineer and company secretary of £1,000 a year. This Thomas Livesey was the nephew of the Chartered's Mr. Livesey. He was the father of George.
Laming had lost the legal battles but the mixture used in the oxide process was always known in the future as 'Laming's mixture'. He continued to work in Millwall on processes for the 'manufacture of ammonia and preparations for the purification of gas'. It was said of his sulphate of ammonia 'nothing can exceed the beauty and purity of the article he thus manufactures'. He appeared less and less in the gas industry minute books and retired in the mid-1860s. He had been involved before 1865 with a journal, The Electrician, in which he put forward 'views on electricity and matter until they grew less and less comprehensible'. He died in 1879, having been bedridden and demented for fourteen years.
Croll's career has already been examined in a previous chapter. Frank Hills continued to flourish. He was supported by his family, in particular his four brothers.