Unknown dart air pistol (c. early 1900s?)

Unknown dart air pistol (c. early 1900s?) 

With thanks to Larry H. He says:

The weird air pistol I have here is a dart pistol (unmarked), but is a true spring-piston air pistol, probably dating from the early 1900's... The darts are muzzle loaded with the included silver plated tool. The unique trigger and sear arrangement reminds me more of a creation from a watchmaker than a gunmaker! I think I covered this piece some years ago in an article.