Happy Hours in Story Land. New York: McLoughlin Bros., 1901.
How kids spent their leisure time before smart phones.
From the Online Etymology Dictionary:
handkerchief (n.) 1520s, from hand + kerchief, originally "cloth for covering the head," but since Middle English used generally as "piece of cloth used about the person." A curious confluence of words for "hand" and "head." By-form handkercher was in use 16c.-19c. A dropped handkerchief as a token of flirtation or courtship is attested by mid-18c.
I'm not up on contemporary courtship etiquette, but is a dropped cellphone today's token of flirtation?