GREEN CARDAMOMS/Gaurangi Maitra
FROM CAVE walls to digital media, materials from plants and animals have coloured our world. Yet, when this material came at a tremendous price it resulted in uprisings like the 1859 Indigo Revolt in Bengal. Thus the industrial revolution which created the market for natural indigo to dye machine produced textiles also created space in the 1800s for synthetic dyes. So, the trobairitz takes you back to three years before the Indigo Revolt when the bright youngster William Henry Perkins was an assistant to the chemist August Wilhelm von Hofmann.
In April 1856, with Hoffman holidaying Germany, Perkins was attempting to synthesizing quinine by oxidising aniline compounds derived from the cheap and plentiful coal tar. When Perkins tried oxidizing allyl toluidine (an aniline derivative) with potassium dichromate, he got not the white crystals of quinine but a black solid that stuck to sides of his apparatus. As he tried cleaning out the black solid with alcohol, the apparatus became clean but the alcohol took on a beautiful purple colour. It made him forget his failure at not getting quinine and he rushed home in excitement with his chance discovery.
The story really picks up pace now and the scene of action shifts from Hoffman’s laboratory at the Royal College of Chemistry to Perkins’ home in Cable Street in London, where a crude laboratory was set up with the help of his father and brother. Perkins concentrated the solution till it became a hard solid. When he boiled this solid in hot water with a little tartaric acid, the purple solution he had first seen reappeared and Perkins a dipped a piece of silk in to this solution. When Perkins took it out, he held in his hands, silk coloured near Tyrian Purple! A close approximation of the colour derived from marine murex species, worn by royalty and reported to fetch its weight in silver in the 4th century BC. Perkins repeatedly washed the coloured silk and the colour did not fade!
At this point Perkins could have either published the discovery in an academic journal and probably crossed swords with his alma mater and mentor or explored its commercial potential; that Perkins chose to do the latter changed his personal fortune and launched the artificial dye industry. By June they sent a sample to Messrs Pullars, in Scotland, who held the Royal Warrant of Dyer to Her Majesty the Queen. Their reply confirmed Perkins and his brother had discovered a possible substitute whose production could be commercially successful. On 26 August 1856, the Patent Office in London granted the 18 year old Perkin a patent for ‘a new coloring matter for dyeing with a lilac or purple colour stuffs of silk, cotton, wool, or other materials’. This new colouring material came to be called Perkin Purple, aniline blue or mauveine.
From Pascal tide to August, Perkins neatly danced out of Hoffman’s shadow and moved from assistant to entrepreneur. Combining active, independent research in organic chemistry with commercial production at his Greenford dye works, Perkins successfully marketed other synthetic dyes and products. When the competition from the German chemical industry became too much, he wisely sold his business 1874 and retired a rich man. The academic world honoured him with the Royal Society and Davy Medals and Queen Victoria knighted him.
When Queen Victoria and Empress Josephine, wore gowns coloured by Perkin Purple, they made the colour fashionable. When Walther Fleming used Aniline Blue to stain chromosomes, it completed the story of cell division. Then, Alfred von Bayer synthesized indigo in1878, and the demand for synthetic indigo replaced the natural by a ratio of 9:1 by 1904; fifty years on, the revolution had come a full circle. From Perkin Purple onwards, the world of synthetic dyes touched every aspect of human life. For successfully balancing science and entrepreneurship and knowing when to draw a line; to the Perkin Purple Millionaire, jai ho!
(Resources: Wikipedia, www.threaction.net and www.mosi.org.uk)