At about the 50 minute mark, Miss Lister said "...smashed to atoms...."
Atoms were not discovered for over 50 years later than when this show is set.
About five minutes into the episode, Anne Lister is at the dinner table talking with Marian Lister. Anne refers to Mister Abbott as somebody who 'dumped' Marian (i.e. terminated a romantic relationship with her). Marian denies that Mister Abbott 'dumped' her.
This episode is set in 1835 but the expression 'to dump' meaning to terminate a romantic or sexual relationship with somebody is of relatively modern origin.