Something I Noticed In The Film The Prestige

I recently watched an older movie that I never got to see before. The Prestige ( 2006) is about two rival magicians ( illusionists) who were former partners . They keep trying to outdo each other throughout the film as the stakes keep getting higher. I noticed what I thought of a gaffe ( at least for the period)


There is a scene where there is a formal inquiry about one of those transparent tanks of water you see onstage. This inquiry is held in London and the units used to describe the capacity of the water tank was gallons. Maybe my assumption they would use  "liters" in 19th century London but that might be just me. Possible that was a concession given to American audiences? Then again maybe gallons was acceptable at the time according to this. 









prestige movie 2006  gallons tank water liters metric