At the opening of this episode, the cast are in conversation about 'robots'. Considering this program is set in the 1890's, and the term 'robot' was not used in the English language until 1920 by Czech playwrite Karel Capek in his play R.U.R. (Rossum's Universal Robots), then, although the program is 'light entertainment', the writers should have given a little more thought to the historical accuracies.