Prim & Proper-T: A Victorian Time Travel Tale

An American family has rented a Victorian house in London, England, for a year.
Thanks to the detailed list supplied by the Prim & Proper-T Real Estate Agency, they know every article of furniture, piece of linen and miscellany, right down to the smallest teaspoon, found in the house.
One item is, however, missing from the list, because one rarely finds the word ‘phenomenon’ on an inventory…