I have some late-19th-century books on plumbing that mention the same passivation layer, and so clearly it was known, along with some of the toxic effects of le

I have some late-19th-century books on plumbing that mention the same passivation layer, and so clearly it was known, along with some of the toxic effects of lead, back when it was widely used for plumbing (which I must also mention that the 'plumb' comes from 'plumbum' - Latin for lead.)