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Sunday, 9 August 2009

Cement

Coal tar products were developed for use in many construction applications. There seems to have been a suspiciously close relationship between manufacturers who bought coal tar and those who claimed to make various fancy ' Roman cements’. For instance Turner, the Poplar tar distiller who had taken over the Chartered Gas Company's tar works, also described himself as a 'Roman cement maker’.

'Roman' cement was one of a number of artificial building materials developed at this time. Ingredients were often not clear and varied with the maker. The poet, Michael Baldwin, writing about cement in North Kent has commented 'I suspect that experts are less clear about what was really in James Parker's Roman Cement than they pretend to be'.

For example, Edgar Dobb of Southwark, had patented a cement the ingredients of which were 'clay, loam, mud, shale, road dirt, soil ochre, metallic oxides, ore, sandstone and earths' ‑in which mixture the addition of a bit of coal tar would probably have gone completely unnoticed.

In a similar vein, A.K. Francis quotes an advertisement from 1845 of 'P. & T.M'Anaspi ....... bitumen cement workers' (which preamble leads incidentally to the question about what exactly is meant by the word 'cement'?) M'Anaspie advertised their product as 'artificial hydraulic cement' and also claimed to make 'artificial stone and patent asphalte.'

Macaroni, more likely to be frank about coal tar, promoted its use in a mix with things, like pebbles and chalk 'to answer every purpose of building'. No doubt it was also cheap.
A list of eleven Roman cement manufactures active in London in the early 1820s is detailed by A.K.Francis. Of these Atkinson, Simpson and Sanders are also all listed as chemical manufacturers. Turner, as we have seen, was also a tar distiller, Morgan was involved with Cassell and Francis and Mornay were gas company subscribers. Seen in this way the manufacture of Roman cement becomes quite clearly a branch of the chemical industry.
Charles, 'Citizen' Earl Stanhope of Chevening was well known to the early gas industry and had even written a letter of support to the Chartered Company before the 1809 Enquiry. He invented a type of cement that included tar - although exactly what sort of tar is a point on which he remained ambiguous. John Nash used Stanhope's tar on the roof of Buckingham Palace where it melted in warm weather, was the subject of some scandal and had to be replaced. General Pasley, who wrote a book on cement, said that the tar used on this occasion was wood tar although coal tar was used in similar installations.

Contemporary comments point to the use of coal tar in similar circumstances and with an equal lack of success.

'Stucco' is another example of something whose constituent parts were far from clear. This popular material had a lime and stone based formula and like 'mastic' it was widely used on the outside of those buildings that were in need of covering 'with great expedition'. Mastic was made with linseed oil although some variants contained whiting, resin and glue. What really went on the walls of buildings, being built with an eye to speed and to keeping down costs, is anyone's guess. In most cases the main aim must have been to cover up quickly whatever it was that had gone up underneath!

'Asphalte' was used both for waterproofing and as a surface material. Advertising material hinted that it came from a Swiss source and was a type of natural bitumen Once again this is more than open to some doubt. George Landmann, Engineer of the London and Greenwich Railway, mentioned above as a gas enthusiast, used 'asphalt as a waterproofing medium on the railway's brick arches'. This came from the Seyssel Asphalt Company - and from evidence given above their most likely location was the Isle of Dogs. Similarly, when the Croydon Railway joined London and Greenwich at London Bridge Station the platforms were covered with 'beautiful specimens of Bastenne bitumen’- another Millwall product.

R.T. Claridge Esq. whose ‘patent asphalte’ has been mentioned above provides a good example of this confusion in the exact nature of ingredients. He patented a 'Mastic cement applicable to paving, and road making, covering buildings and various other purposes'. In 1838 a case for patent infringement between Claridge and a Mr.Latrade was heard. Latrade had actually intended to use 'mineral pitch' in a paving scheme but had somehow found himself using 'Stockholm tar'. There was much discussion in court on the two patents - and unsurprisingly Claridge's specification was said to be unclear on the subject of the type of tar. Specimens of coal tar from the City Gas Works were produced in evidence and passed round the jury so that they could see what they thought the difference was.

The likelihood is that there were as many mixes as there were manufacturers and that they mostly kept the contents of their mixtures to themselves.

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