TL;DR: Mercury Chloride was sold as a powerful laxative referred to as "thunder clappers" which enabled the Lewis and Clark expedition could manage on a meat-he

TL;DR: Mercury Chloride was sold as a powerful laxative referred to as "thunder clappers" which enabled the Lewis and Clark expedition could manage on a meat-heavy diet and the occasional syphilis. Last paragraph sums it up nicely: So as Lewis and Clark’s men made their way across the continent and across Oregon, they were unknowingly depositing a trail of heavy metals along the way – a trail that historians and scientists have been able to detect and use to document almost their every movement, so to speak.