I've just been lent a "The Sir Isaac Newton Razor" to have a play with but would like to find out more about it. Either links or personal knowledge / experience would be good

It's not in great condition, it's become tarnished and has been very aggressively sharpened in the past and I think the end has been re profiled, but I'd quite like to restore it if it's going to end up being a good shaver.