When elderly policeman reads the last will of the deceased, there is a rap sheet on the wall with fingerprints and front-and-side mughots. However, movie takes place in 1876 while dactyloscopy has not been introduced into police procedure until 1891 (and gained popularity even later) while front-and-side mughots were first used in the first years of 20th century.
When Lady Esther shows baron Evert-Kokoltsev kids playing in laboratory, there is a Wimshurst machine on the table. However, this contraption was developed after 1880 while the movie is set in 1875. Distinctive oblong inserts show that this is machine of Wimshurst's design, not the period-appropriate generator designed by Holtz or Toepler.