All the footage has been cut together into a six-minute movie that Mr Park, who lives in Henham, Essex, describes as 'in support of the British First World War effort'.
Mr Park bought the film container 'from someone else who deals in bits and bobs' and did not even open the parcel after it arrived.
When he did, he spotted the film's title after unrolling part of it and decided to search for it online.
He said: 'I Googled it and then my interest was pricked. I couldn't find any sign of it on the internet.'
Mr Park said: 'It starts with live shots of Chaplin. It then turns into a dreamscape.
'We see a Zeppelin bomb attack. And then we see Chaplin taking the mickey out of the Zeppelin, at the time a powerful instrument of terror,' he told The Guardian.
The movie, shot on 35mm nitrate film, is believed to have been a First World War propaganda piece aimed at lessening the fear of airship bombing raids which Germany had been launching on Britain from the beginning of 1915.