Poison Green
'Green is the prime color of the world, and that from which its loveliness arises.' - Calderon de la Barca
After Waterloo, Napoleon spent the rest of his life in exile on St. Helena; destiny dictated that he would be born on one island and die on another. He lived in Longwood House, where the walls were papered - in green. Bright green. But this was no ordinary green.
It was Scheele's Green, and unbeknownst to Napoleon, it was deadly.
Isaac Asimov dubbed Swedish chemist Carl Wilhelm Scheele (1742-86) 'hard-luck Scheele'. Scheele was not a lucky man. Not only did consistent exposure to toxic materials cut his life short, Scheele made discoveries others would take credit for. And as luck would have it, he is best remembered for the shade of green that may have helped kill Napoleon Bonaparte.
The vivid green followed a brilliant yellow Scheele produced in 1770. He mixed litharge (powdered lead oxide; PbO) with muriatic or hydrochloric acid (HCl), then waited for twenty-four hours before applying heat. As if by magic, the color changed from white to a dazzling shade of yellow. English paint manufacturer James Turner knew a good thing when he saw it, patenting the process in 1781. But Turner's Yellow turned black if exposed to water. Worse, the fumes it gave off were affecting coach-painters (and yellow was the most popular color). Scheele's next color, his infamous green, would give off fumes, too. But these were not noticed, rendering the poison it produced all the more insidious.
Scheele's Green may or may not have been invented accidentally. The process was certainly tedious: two pounds of blue vitriol (crystalline copper sulphate, CuSO4.5H2O) poured into three gallons of boiling water. Two pounds of pearl ash (potassium carbonate, K₂CO₃) were added to a separate gallon of water, along with eleven ounces of arsenic. The mixtures were filtered, then the solution of blue vitriol was added while hot to the pearl ash and arsenic solution little by little. The resulting 'sediment' was 'washed with cold water.'
Scheele knew perfectly well that the arsenic presented a problem, as a letter he wrote to a friend reveals. His conscience plagued him; consumers out to be apprised. But they were not and his green became very popular; not only was it was inexpensive to produce, it was the most natural green pigment to date, without a hint of blue or yellow or grey or brown.
Napoleon may have admired the green wallpaper at Longwood House, insouciant in that he nor anyone else knew how toxic Scheele's Green was. Microscopic, arsenic-laden particles could flake off and be aspirated. Worse, the damp climate of St. Helena almost guaranteed that the wallpaper would mold. (Even today, Longwood House is repapered every few years.) But when arsenic-laden Scheele's Green was exposed to mold, a chemical reaction produced toxic arsine gas.
Napoleon may very well have died of stomach cancer, afflicted with persistent nausea and plagued with severe stomach pain. He lost his strength. ('Everything for me', he confided to his doctor, 'is a Herculean task.'). And he lost at least twenty pounds during the last six months of his life, the trousers made for him getting smaller and smaller. Finally, stomach cancer did not run in the Bonaparte family: it seems to have galloped, believed to have killed Napoleon's grandfather, father, brother Lucien - and three sisters. But breathing in arsenic may have hastened his death.
A sample of his hair was analysed in 1961, revealing an elevated level of inorganic arsenic in his bloodstream. The FBI was sufficiently intrigued by whispers of deliberate poisoning to test another sample in 1994: it too revealed large amounts of inorganic arsenic. However (as the FBI pointed out) there was no control available: who could say in the late 20th century what a typical level of inorganic arsenic in the bloodstream had been two centuries earlier? Napoleon loved wine. Arsenic was used to dry out casks. It was used in vineyards, as a pesticide. If he suffered from venereal disease, he would have been treated with mercury. Or arsenic. But the arsenic Napoleon was inhaling round the clock - he was bedridden for the last five weeks of his life - may have been the proverbial straw that broke the camel's back.
Deliberate poisoning should not be ruled out. Even if Napoleon had stomach cancer - his post-mortem revealed coagulated blood resembling coffee grounds in his stomach, as well as a host of lesions - his rapid decline may have been deemed not rapid enough. (Shades of Amy Robstart.) Napoleon was certainly suspicious: 'I die before my time, murdered by the English oligarchy and its assassin.' The inevitable could have been sped along with steady small doses of rat poison. Arsenic was (and is) used to poison rats. And St. Helena was infested with rats. Once after dinner at Longwood House, Napoleon reached for his hat before leaving the house and out popped a rat! (The dining-room was particularly infested.) Servants with sticks and dogs made little difference.
Napoleon died in 1821, seven years after chemists in Schweinfurt, Bavaria developed produced a new bright green pigment. Schweinfurt Green (or copper acetoarsenite) was better than Scheele's Green: more durable, more lightfast, and did not darken with repeated exposure to sulfides in the air given off by burning coal. But it was just as toxic as its predecessor. This time around, it was common knowledge that this bright green pigment was laden with arsenic as early as 1822. But it became very popular, sold under different names such as Vienna Green and Paris Green, after it proved an effective rodenticide in the Paris sewers. In 1839, ballgowns were dusted with it and when the ladies danced it came loose, producing clouds of a dazzling green. (Meanwhile, everyone breathed in a dose of poison.)
Sold as Emerald Green to painters, it was embraced by everyone from J. W. M. Turner to Monet to Gauguin. Manet combined Scheele's Green (available still) with Emerald Green when painting Music in the Tuileries (1862; National Gallery, London). (Landseer was the last painter of note to use Scheele's Green, in 1866.) By this time, Emerald Green was very much in vogue and would be for decades. Cézanne was a fan. Odilon Redon used it in pastel form in the early 1890s. The last painter of note to use Emerald Green was Childe Hassam in 1917 after it had been banned. (It was in use as late as the 1960s.)
NAPOLEON’S RESIDENCE
Whatever shall we do in that remote spot? Well, we will write our memoirs. Work is the scythe of time.
Napoleon, in reference to his impending imprisonment on St Helena
Napoleon loved green. It was his favorite color. In 1775, when he was six years and lived in Corsica, a new shade of green was invented by a Swedish chemist that had the enviable quality of mimicking nature. If there was no verdant landscape to admire nearby, one could (assuming one could afford it) paper one's wall in this brilliant shade of green. Napoleon, in reference to his impending imprisonment on St Helena
After Waterloo, Napoleon spent the rest of his life in exile on St. Helena; destiny dictated that he would be born on one island and die on another. He lived in Longwood House, where the walls were papered - in green. Bright green. But this was no ordinary green.
It was Scheele's Green, and unbeknownst to Napoleon, it was deadly.
Isaac Asimov dubbed Swedish chemist Carl Wilhelm Scheele (1742-86) 'hard-luck Scheele'. Scheele was not a lucky man. Not only did consistent exposure to toxic materials cut his life short, Scheele made discoveries others would take credit for. And as luck would have it, he is best remembered for the shade of green that may have helped kill Napoleon Bonaparte.
The vivid green followed a brilliant yellow Scheele produced in 1770. He mixed litharge (powdered lead oxide; PbO) with muriatic or hydrochloric acid (HCl), then waited for twenty-four hours before applying heat. As if by magic, the color changed from white to a dazzling shade of yellow. English paint manufacturer James Turner knew a good thing when he saw it, patenting the process in 1781. But Turner's Yellow turned black if exposed to water. Worse, the fumes it gave off were affecting coach-painters (and yellow was the most popular color). Scheele's next color, his infamous green, would give off fumes, too. But these were not noticed, rendering the poison it produced all the more insidious.
Scheele's Green may or may not have been invented accidentally. The process was certainly tedious: two pounds of blue vitriol (crystalline copper sulphate, CuSO4.5H2O) poured into three gallons of boiling water. Two pounds of pearl ash (potassium carbonate, K₂CO₃) were added to a separate gallon of water, along with eleven ounces of arsenic. The mixtures were filtered, then the solution of blue vitriol was added while hot to the pearl ash and arsenic solution little by little. The resulting 'sediment' was 'washed with cold water.'
Scheele knew perfectly well that the arsenic presented a problem, as a letter he wrote to a friend reveals. His conscience plagued him; consumers out to be apprised. But they were not and his green became very popular; not only was it was inexpensive to produce, it was the most natural green pigment to date, without a hint of blue or yellow or grey or brown.
Napoleon may have admired the green wallpaper at Longwood House, insouciant in that he nor anyone else knew how toxic Scheele's Green was. Microscopic, arsenic-laden particles could flake off and be aspirated. Worse, the damp climate of St. Helena almost guaranteed that the wallpaper would mold. (Even today, Longwood House is repapered every few years.) But when arsenic-laden Scheele's Green was exposed to mold, a chemical reaction produced toxic arsine gas.
Napoleon may very well have died of stomach cancer, afflicted with persistent nausea and plagued with severe stomach pain. He lost his strength. ('Everything for me', he confided to his doctor, 'is a Herculean task.'). And he lost at least twenty pounds during the last six months of his life, the trousers made for him getting smaller and smaller. Finally, stomach cancer did not run in the Bonaparte family: it seems to have galloped, believed to have killed Napoleon's grandfather, father, brother Lucien - and three sisters. But breathing in arsenic may have hastened his death.
A sample of his hair was analysed in 1961, revealing an elevated level of inorganic arsenic in his bloodstream. The FBI was sufficiently intrigued by whispers of deliberate poisoning to test another sample in 1994: it too revealed large amounts of inorganic arsenic. However (as the FBI pointed out) there was no control available: who could say in the late 20th century what a typical level of inorganic arsenic in the bloodstream had been two centuries earlier? Napoleon loved wine. Arsenic was used to dry out casks. It was used in vineyards, as a pesticide. If he suffered from venereal disease, he would have been treated with mercury. Or arsenic. But the arsenic Napoleon was inhaling round the clock - he was bedridden for the last five weeks of his life - may have been the proverbial straw that broke the camel's back.
Deliberate poisoning should not be ruled out. Even if Napoleon had stomach cancer - his post-mortem revealed coagulated blood resembling coffee grounds in his stomach, as well as a host of lesions - his rapid decline may have been deemed not rapid enough. (Shades of Amy Robstart.) Napoleon was certainly suspicious: 'I die before my time, murdered by the English oligarchy and its assassin.' The inevitable could have been sped along with steady small doses of rat poison. Arsenic was (and is) used to poison rats. And St. Helena was infested with rats. Once after dinner at Longwood House, Napoleon reached for his hat before leaving the house and out popped a rat! (The dining-room was particularly infested.) Servants with sticks and dogs made little difference.
Napoleon died in 1821, seven years after chemists in Schweinfurt, Bavaria developed produced a new bright green pigment. Schweinfurt Green (or copper acetoarsenite) was better than Scheele's Green: more durable, more lightfast, and did not darken with repeated exposure to sulfides in the air given off by burning coal. But it was just as toxic as its predecessor. This time around, it was common knowledge that this bright green pigment was laden with arsenic as early as 1822. But it became very popular, sold under different names such as Vienna Green and Paris Green, after it proved an effective rodenticide in the Paris sewers. In 1839, ballgowns were dusted with it and when the ladies danced it came loose, producing clouds of a dazzling green. (Meanwhile, everyone breathed in a dose of poison.)
Sold as Emerald Green to painters, it was embraced by everyone from J. W. M. Turner to Monet to Gauguin. Manet combined Scheele's Green (available still) with Emerald Green when painting Music in the Tuileries (1862; National Gallery, London). (Landseer was the last painter of note to use Scheele's Green, in 1866.) By this time, Emerald Green was very much in vogue and would be for decades. Cézanne was a fan. Odilon Redon used it in pastel form in the early 1890s. The last painter of note to use Emerald Green was Childe Hassam in 1917 after it had been banned. (It was in use as late as the 1960s.)
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