Except he's talking to somebody who lived through the same time period, and who has already guessed from a variety of things that John is from sometime in the past, from the time he got taken. This is just another check in the "early 20th century" check list.

"It took me a little while to get used to showers when they became popular," Jack allows. "But they're very convenient. I never quite managed the two-minute shower, but it's still much quicker and easier than drawing a full bath."