LITMIR.BIZ

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used not only as dye and pigment but also an astringent lotion, derived from the leaf of Indigofera tinctoria, a shrublike plant that was soaked in water and then beaten with bamboo to hasten oxidation. During this process the liquid changes colour from dark green to blue, when it is then heated, filtered and formed into a paste. Before the colonisation of America, it came predominantly from India in the form of dye-cakes, and this ancient derivation held firm to the time when Perkin could observe the colour in women’s fashions in the West End.

      There were several other important plant dyes – carthamus, woad, saffron, brazilwood and turmeric – but even these represented an extremely narrow range of colours, confined variously to red, blue, yellow, brown and black. Woad, again known to Pliny and used commonly by ancient Britons as a facial and body dye, contained a similar colouring matter to indigo, although derived from a different plant and containing about one-tenth the tinctorial power.

      Throughout much of the eighteenth century the greatest advances in dyeing technique were made in France, but between 1794 and 1818 an American working in London called Edward Bancroft claimed many significant improvements. Bancroft patented three new natural dyes, including the yellow quercitron, and wrote the first scientific treatise on dyeing in English. His Experimental Researches Concerning the Philosophy of Permanent Colours combined exact chemical observations with personal anecdotes: he noted, for example, how his favourite purple coat hardly faded though he wore it for several weeks. Bancroft had a further claim on posterity, as he was later exposed as a double agent during the American Revolution, working both for the British government and for Benjamin Franklin.

      The process of dyeing cloth had not changed much in centuries, and the most skilled practitioners had passed complex and guarded procedures through generations. But in New York in 1823, William Partridge published A Practical Treatise on Dyeing of Woollen, Cotton and Skein Silk, with the Manufacture of Broadcloths and Cassimeres Including the Most Improved Methods in the West of England, for thirty years the standard text, in which all the most popular dyes were disclosed like magicians’ secrets and presented like cookery recipes. To prepare the fastest blue, for example, you would need an English vat containing ‘five times one hundred and twelve pounds of the best woad, five pounds of umbro madder, one peck of Cornell and bran, the refuse of wheat, four pounds of copperas, and a quarter of a peck of dry slacked lime’.

      There were detailed descriptions of how to prepare the lime, followed by directions to chop the woad into small lumps with a spade, and gradually add other ingredients to water set at 195 degrees Fahrenheit. The instructions ran on for several pages. ‘The vat should be set about four or five o’clock in the afternoon, and be attended and stirred again at nine o’clock the same evening,’ before being cooled. By this stage the result should be bottle-green. The dyer was then directed up again at five in the morning, and told to add more lime or indigo to lighten the colour. Bubbles and skin and increasing thickness would denote a good fermentation, which should then be boiled again and cooled, and boiled and cooled, and more lime added, and then it was time for the wool dipping. This was where matters became complicated. You really needed two vats of woad, one two months old, the other new, and the wool should be dipped in each in turn. The temperatures of the dye should be finely held at 125°F–130°F, then cooled overnight, then heated to 155°F–165°F, and then more woad added, with more lime, bran, madder and indigo. If the vats were skilfully managed it should colour 220 pounds of wool every week; within six weeks, the dyer should have four hundred pounds of dark blue wool, two hundred of half-blue, and two of very light. But this was only attainable if the very best woad and indigo were used, and here there were problems: ‘There is probably no article more uncertain in its strength and quality than woad,’ Partridge concluded. He advised buying only the very strongest, as ‘any considerable variation in this particular will prove very disastrous to the operator, however skilful he may be in his profession, and will be altogether ruinous to a young beginner’.

      As with cinchona bark, the supply of plant dyes was often limited to specific regions and hampered by a nation’s attempts to monopolise production. Clothes manufacturers were forced to use the colours available in the dyers’ vats; trends in colour were fashioned less by taste than by the vagaries of war and efficiencies of foreign ports. It stood to reason that a colour you could make on demand in a laboratory somewhere, with a constant strength and purity, would surely be worth an awful lot of money.

      Initially, Perkin called his discovery Tyrian purple, the better to elevate its worth. His detractors, those who believed his discovery insignificant, preferred to call it purple sludge. Chief amongst these was August Hofmann, who learnt of Perkin’s new colour after the summer holidays, along with some distressing news of his protégé’s future. The two arranged a meeting, during which Perkin told Hofmann that he was considering manufacturing mauve commercially. He also said that this would require him to leave the Royal College of Chemistry. ‘At this he appeared much annoyed,’ Perkin recalled at a memorial meeting to mark Hofmann’s death in 1892. ‘[He] spoke in a very discouraging manner, making me feel that perhaps I might be taking a false step which might ruin my future prospects.’

      The objection caused a serious rift between them – probably the first cross words they had exchanged. ‘Hofmann perhaps anticipated that the undertaking would be a failure, and was very sorry to think that I should be so foolish as to leave my scientific work for such an object, especially as I was then but a lad of eighteen years of age. I must confess that one of my great fears on entering into technical work was that it might prevent my continuing research . . .’^*

      Hofmann and his colleagues would have found it hard to imagine how one of the most promising scientific careers could be summarily abandoned in pursuit of a colour. Chemists came across new colours at random almost every week, and just as easily dismissed them as being an undesirable or irrelevant side-effect of their missions. Besides, some chemists had deliberately produced artificial dyes before mauve, and had observed how well they had coloured silk or wool, but had not attempted to manufacture them in commercial quantities. The first had been the picric acid made by Woulfe in 1771 from indigo and nitric acid (it dyed silk bright yellow), and in 1834 Runge had used carbolic acid to make aurin (a red colour), and pittacal (a deep blue) was obtained from beechwood tar. Other colours encouraged the development of implausible histories, not least murexide, which surfaced in small quantities in Manchester dye works in the 1850s and was said to come from the excrement of serpents (rather than its true source, bird-droppings). But the quantities of synthetic dyes in use at the time of the Great Exhibition of 1851 was so small as to not merit any mention in the huge accompanying Reports.

      Then there was the bright crimson produced by Perkin and Church some months before, again considered unworthy of further exploitation. Perkin’s purple might have been cast aside in a similar manner were it not for the further encouragement he received from Robert Pullar in Perth towards the end of 1856.

      The scale of Pullar’s dye works must have seemed an impressive place to a young man unfamiliar with industrial practices. The presence of scientists, however, was nothing new to print works, and some had employed their own textile chemists from 1815. In fact, Perkin’s discovery came at a time when the state of technical advance in Britain’s dye and printing works was ideally poised to exploit it. Production levels in the textile industry were increasing at unprecedented rates. Exports in the calico business, for example, increased fourfold between 1851 and 1857, from about 6,500,000 items to 27 million. Employment in the silk industry doubled to 150,000 people between 1846 and 1857. At one of the many jubilee celebrations of Perkin’s discovery, the chemist C. J. T. Cronshaw told a gathering of the Society of Chemical Industry: ‘If a fairy godmother had given Perkin the chance of choosing the precise moment for his discovery, he could not have selected a more appropriate or more auspicious time.’

      This was not only true of the position of Britain’s dye works. Perkin could only have discovered mauve when he did because of the particular state of chemical knowledge. He was born not long after the Cumbrian chemist John Dalton had theorised that atoms combine with each other in definite numbers, thus leading to the establishment of chemical formulae. But Perkin conducted his early experiments at a time when so much was yet unknown, thus allowing for his productive error over the synthesis of quinine. If Perkin had been born twenty years later, he would have known how fruitless his

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