How Long Is “Bobby Bumps' Disappearing Gun”?

Bobby and Fido, hidden behind a snow bank, have a contraption that folds down and expands upwards. It is gradually revealed to be a snow ball gun. It is replete with a scope that Fido looks through to comment on their aim ("too high," "too low"). They successfully knock the top hat off a passing gentlemen two times in succession. Then they hit a washer woman in the head. She pursues them, getting pelted as she approaches the snow bank. Bobby and Fido take flight, pulling the gun on a small cart behind them. The washer woman runs after them. They climb a hill leaving marks in the snow. The washer woman follows.