Mt Vesuvius eruption on 5 April 1906, and killed more than 100 people; it ejected the most lava ever recorded from a Vesuvian eruption. Therefore, this episode was set shortly afterward.
The $1 that Higgins makes per day in 1906 is worth nearly $29 in 2020.
This episode has Murdoch working on inventing an automatic dishwasher. The first mechanical dishwashing device was registered in the United States in 1850. The most successful of the hand-powered dishwashers was invented by Josephine Cochrane in 1886, and was unveiled at the Chicago World's Fair in 1893.