Isaac Newton’s description of the taste of mercury.
However, mercury wasn’t the only toxic substance that Newton ate during his alchemy experiments. He also tasted arsenic, gold and lead. But even though these chemicals are toxic, and even possibly fatal, it was the mercury that most likely caused his death, and erratic mental behavior from time to time. How can we be certain?
During a period of 18 months between 1692 and 1693, Isaac Newton suffered from sever mental problems. He had symptoms of depression, insomnia, loss of appetite, amnesia and even delusions. And this was when he was only 50 years old. He still had another 34 years of life left in which to develop dementia. While it is possible that some of the other chemicals that he worked intimately with could have caused the same symptoms, mercury is by far the best fit. The symptoms also closely resemble those of the mad hatters, or the hat makers who used the heavy metal mercury to form mats. But the closeness of symptoms isn’t enough to determine that Isaac Newton died eating mercury. Better analysis was needed.
When his body was exhumed they detected large quantities of mercury in his hair. These large quantities would definitely explain his bizarre behavior during his 18 months of madness, and the eccentricities in later life. So it certainly was possible that Isaac Newton died eating mercury, but the death was greatly delayed.