Interesting question, presumably it was a Gat type Air Pistol if you are only considering machine made in bulk items, but I don't know that, it's only a guess. I believe that Westley Richards were early 20C from around 1907 onwards, with Lincoln Jeffries pistols a few years later, but I'd be interested to hear what came before, presumably something along simpler lines ?
If you count limited production specialist made items such as Bellows Guns and Gallery pistols, maybe the timeline slips back a couple of Centuries at least.
Vic Thompson.