1930s dating rules
Dance marathons are events in which people dance or walk to music for an extended period of time.
Dance marathons, endurance movement contests, and derbies can be traced back to London in 1364.
Previous convention said a chaperone was needed in order to engage in courtship, but these "wild young people" (as one publication referred to them) bucked tradition.
popularized the idea and prompted students at Northwestern University, Pennsylvania State University, Indiana University, Ohio State University, the University of Florida, and the University of North Carolina at Chapel Hill to create charity dance marathons.
The patent may only refer to a certain combination of scales used over a thirty year time on different models. 1911 James Dieterich, who has worked his way up to blueprint foreman at B. Makepeace Co., goes west and lands a job as a salesman with the K&E branch in San Francisco. In general the production rate was about 70,000 rules per year until the 1950s. The 1960s had a production rate of about 100,000 per year for several years and tapering off in the 1970s ending at about 700000.
Having contact with the original owner of a slide rule that remembers the year it was purchased helps on determining the age. In general it is safe to assume a linear production rate between the rollover dates particularly for the common types rules.
The 1915 rules are attributed to a Sacramento teachers’ contract and elsewhere to an unspecified 1915 magazine." According to Snopes, the fact-checking web site, the 1872 list has been "displayed in numerous museums throughout North America," over the past 50 years, "with each exhibitor claiming that it originated with their county or school district." Heck, the lists even appeared in the venerated Washington Post not so long ago. Teachers will fill the lamps and clean the chimney each day. Each teacher will bring a bucket of water and a scuttle of coal for the day's sessions. He should use his savings during his retirement years so that he will not become a burden on society. Any teacher who smokes, uses liquor in any form, visits pool halls or public halls, or gets shaved in a barber shop, will give good reasons for people to suspect his worth, intentions, and honesty. The teacher who performs his labor faithfully and without fault for five years will be given an increase of twenty-five cents per week in his pay. You will not marry during the term of your contract.
via Peter Kaufman, mastermind of the Intelligent Channel on You Tube.