nitrous

well, I am not sure that is true. Many technical skills of the ancients have been lost and are not reproducible by the best of the best, modern (wo)men! Many of the classic colored dyes of the ancient world are still only approximated by modern science. We still don't know, with certainty how the pyramids were built. We certainly don't know how, to any degree of certainty how the ancients limited understanding of astronomy and mathematics could build Stonehenge. There are many things we can do that lead to information beyond our understanding. Information, Knowledge and Wisdom are 3 very different things. But having said that, and with only limited material sciences under my belt (was a physical chemist before medicine ) I don't doubt there are many metallurgical question from the past that are yet to be answered. The "science of metal hardening" is far from settled. We aren't nearly as smart as we think we are nor the ancients as uninformed as you might think. Take care, Doug excellent summary of debate on the internet! Thanks JHCC