110 years ago, a young John Long of Leechburg, PA, sent in this self-explanatory idea for building an alarm clock to the “Young Edisons” department of Popular Electricity magazine.

The magazine carried the feature of letters from readers of its Junior Department. Letters were to accurately and briefly describe experiences in the making and operation of electrical devices and the performance of electrical experiments. The magazine asked readers, “see how good an ‘engineering report’ you can make of your investigations.”

Young Mr. Long constructed this alarm switch with a battery, door bell, and pocket watch.

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