Try to find the spot where the photographer was standing.
That is some belt! I bet it was great sport when it parted?
You'd probably want to stand back a ways.
A return flue portable steam engine, 1890s
Are my eyes deceiving me or does the caption on the image use the verb form "thrashing" rather than "threshing"?
It does indeed! It's a spelling variation that comes up from time to time.