Your answer will be available when you show us the oxygen in Hydrochloric acid....
As I said before, the common acids available to him were generally oxygen component, leading him to incorrectly assume it was a characteristic of acids in general. However, at the same time, the English scientists asserted that the common element was hydrogen, which was in fact correct.
However, error does not disqualify a scientist as much as superstition, which was implied, that I point out was not the case.