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Sunday, 9 August 2009

Wood preservation using gas works tar

One of the best known applications of coal tar is as a wood preservative. As railways, telegraphs and other outdoor users of wood proliferated so the need for preservation became more pressing. Several methods were tried which appear to use gas industry derivatives.

In 1814 a Royal Society Enquiry into the gas industry had been set up because of 'general alarm' raised through an explosion in the 'searing house' at Woolwich Dockyard. This had occurred two years earlier when a Mr. Lukin had experimented there with a new method of seasoning timber. Samuel Clegg giving evidence at the Select Committee into the Chartered in 1823 described Lukin as 'a partner of mine'. This comment seems to suggest some sort of liaison with the early gas industry, in which Clegg was, of course, a leading figure.

What Mr. Lukin actually used is not particularly clear. John Maiben a saddler of Perth who wrote on the early gas industry claimed that he was using 'naphtha’. Clegg said that it was 'wood gas' and Lunge, writing a century later, said that it was 'creosote oils or similar substances in a state of vapour'. Mechanics Magazine contented themselves by describing it as a 'secret process'. Lunge was probably right in his comment that it 'could not possibly answer'.

A number of methods of wood preservation gradually became available that depended on the forcing of a preservative into the wood. Several works to undertake this sprang up in the Millwall area.

Sir Humphrey Davy’s brother, John, researched a process using chloride of zinc. This was patented in 1838 by Sir William Burnett, the Inspector General of the Medical Department of the Navy , as a disinfectant. This action on his part which led to much outrage among the medical profession. In 1851 a works in Millwall was described as owned by the 'Proprietors of Sir W. Burnett's patent for manufacturing and disinfecting timber, corded cloth, wool, etc. The company did not leave Millwall until the 1970s by which time it functioned as a timber importer. It still carries on business in Cuffley, in Hertfordshire.

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