Who first recognized that hydrogen was a discrete substance? [SEP] Hydrogen gas was first artificially produced in the early 16th century, via the mixing of metals with acids.
entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment