Did You Know That Eleven and Twelve Make 23?

"What time is it down there?" "Just eleven." "It's twelve up here—you know eleven and twelve make 23." Handwritten: "Did this ever occur to you?"

So what does the mother mean by yelling "eleven and twelve make 23" down at the couple hanging out on the hammock in the front yard at midnight?

To understand the humor of this postcard from 1909, it helps to know that a fad about the meaning of the number "23" became wildly popular in the United States in the early twentieth century. Beginning around 1906 or 1907, "23"—along with "23 skidoo"—came to be used as a shorthand way of telling someone to "scram," "beat it," or "get lost," usually with a humorous or joking connotation.

Referring to "23" in unexpected ways—as on this postcard or on a valentine—and even placing "23" in surprising places (like on the front of a painted automobile prop in a novelty photo) was a humorous way to let others in on the joke.

So it's obvious that mom is keeping tabs on her daughter as she watches the couple from the second-floor window. And her reference to "23" makes it clear (to those in the know, at least) that she wants the guy to skedaddle.

Postmark, address, and handwritten note on the other side of this postcard:

Omaha & Ogden R.P.O. [railway post office], Apr 1, 1909.

Miss Hazle Hainline, Grand Island, Neb., 222 W. 6th St.

Hello Girlie, wish I could have had the pleasure to set and hear you sing and play tonight. How is mama and dad. Tonight is the first I have eaten since I left your place. Haven't been hungry. Mora.

113 Pub. by Keller Bros., Portland, Or.