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The history of the raincoat |
We know that in 1819 Charles Macintosh contracted with the Glasgow Gas Works to receive some of their waste products, namely tar and ammoniacal water, for a number of years (Hancock, Narrative, p.v).
Tar is the goo that is left when the gas has distilled off from coal. 'Ammoniacal water': sometimes the word 'ammonia' is used to refer to what is understood chemically, strictly speaking, to be ammonia dissolved in water. At ordinary temperatures and pressures ammonia, NH3, is a gas. Naptha Cudbear was a dye based on a substance found in a lichen. Ammonia was used to extract it. Wikipaedia says: "Cudbear was developed by Dr Cuthbert Gordon of Scotland: production began in 1758, and it was patented in 1766. The lichen is first boiled in a solution of ammonium carbonate. The mixture is then cooled and ammonia is added and the mixture is kept damp for 3-4 weeks. Then the lichen is dried and ground to powder." |
Though it is difficult to confirm the dates, it seems that at one time Charles was managing the firm his father had founded, George Macintosh and Co., which manufactured the dyestuff known as 'cudbear'.
On the assumption that the dye-stuff trade was what he had in mind, Charles would have wanted the ammoniacal water for the process of extracting the dying agent from vegetable matter (a lichen).
But he also contracted to receive tar. What would he have had in mind for that?
Woodruff says Charles thought of the tar as a possible solvent the dye extraction process and that having obtained it for that reason subsequently had the idea that it might serve as a solvent for rubber (Woodruff, p. 3) .
But I think this is probably a misunderstanding.
There was already a good solvent for the dye extraction process - ammoniacal water - and one which, since the production of town gas began in earnest, could hardly have been available more cheaply. On the other hand, engaged in the chemical business in Glasgow, and in a powerfully entrepreneurial environment, Macintosh was alert to the possibility of turning other cheap materials into money. The coal tar derivative naphtha was known to dissolve rubber. And coal tar was now almost freely available from gas works. His idea from the outset was likely to have been that just as the waste ammoniacal water was being monetised as a solvent in the dye extraction process, so cheap tar could conceivably be monetised too, by being used as a highly economic solvent for rubber. This actually is how I read the account given by Charles' son George in his Memoire:
" Upon the introduction of coal gas in Britain for the purposes of lighting apartments, and the streets of towns and cities, the manufacturers of the article found that the tar and other liquid products resulting from the process accumulated upon their hands, in the shape of a most disagreeable and inconvenient nuisance. Mr. Macintosh, chiefly with the view to the production of ammonia to be employed in the manufacture of Cudbear, entered, in 1819, into a contract with the proprietors of the Glasgow gas works, to receive for a term of years the tar and ammoniacal water produced at their works. After the separation of the ammonia in the conversion of the tar into pitch, to suit the purposes of consumers, the essential oil termed naphtha is produced; and the thought occurred to him of its being possible to render this also useful, from its powers as a solvent of caoutchouc, or india rubber."
(George Macintosh's Memoire, quoted in Hancock, Narrative, p.vi.)
So, pace Woodruff, Macintosh's thought in connection with gas works was surely that here was a cheap source of a known solvent of rubber and therefore the possibility of another profitable business.
So of course it proved.
Macintosh's technique was to spread the dissolved 'rubber' (with a kind of paint brush) on a fabric surface. Allowing the solvent to evaporate left the fabric with a layer of 'rubber' adhering to its surface.
Others had done something of the kind previously, using other substances as solvents, but the proofed cloth produced by them was apparently less satisfactory. Macintosh's cloth was not perfect either, since the rubber remained odorous and tacky, but he was able to remove one of these problems by simply sticking two rubbered cloths together, rubber to rubber. Thus was formed the robust waterproof material out of which his first 'double-texture' waterproof cloaks were made. (Hancock, Narrative, p.v ; Woodruff, p.3)
Hancock goes on to say that following the registering of a contract for his process in 1823, Charles began to make waterproof articles in Glasgow - but then moved this manufacture to Manchester, establishing with others the firm of Charles Macintosh and Co. (Hancock, Personal Narrative, p.v.)
It is difficult to absolutely sure of the dates here. The patent was taken out in 1923, but exactly when the manufacture under it began in Manchester is not clear. One secondary authority (Ian Miller) says 1924, but I can't work out what this is based on.
Nor is it clear why Charles found it desirable to move. One would have thought that everything would have favoured developing the waterproofing business in Glasgow, where Charles had his roots, where he already had industrial premises, and where he moved amongst the city's powerful industrial elite. It has been suggested that despite these advantages he found it impossible to raise the necessary capital for the new venture, capital which was however available in Manchester.
