So was the film (in the fun sense). It would be nice if they hadn't used every American in London joke, but....
A few pernicity points, which I probably ought to put in a cut.
1) Charles Spencer Chaplin was only 2 years old when the last murder attributed to Jack The Ripper occurred, and the last generally accepted Ripper murder was the year before he was born. Arthur Conan Doyle fits in that time period though.
2) They picture a sailing vessel between two of the bridges that don't raise, and its mast is too high. emperor reckons that tall-masted-ships probably wouldn't ever go upriver of Tower Bridge at all.
3) A frigging machine gun? OK, it is plausible I guess that you could make something like in the appropriate era - after all the Navy had Nock's Volley Gun in 1779, and other similar weapons existed, but...
a) The gun in the film has a modern ammunition feeding mechanism, I don't think anything like that would be within the technology.
b) It was supposed to be the `first of its kind', but that's a productised example they have, not an engineer's prototype!
I'm sure there were others I've missed.