In the fall of 1937, Ed Keefer was a senior in the school of engineering at the University of Toledo in Ohio. Tall, slender, and bespectacled, Keefer was the president of the calculus club, the vice-president of the engineering club, and a member of the school’s exclusive all-male honor society. He also invented the Cupidoscope.

The electrical device could not have been more perfectly designed to bring campus-wide fame to its creators, Keefer and his less sociable classmate John Hawley. It promised to reveal, with scientific precision, if a couple was truly in love. As the inventors explained to a United Press reporter as news of their innovation spread, the Cupidoscope delivered on its promise “in terms called ‘amorcycles,’ the affection that the college girl has for her boyfriend.”

Built in the school’s physics laboratory, the Cupidoscope was fashioned from an old radio cabinet, a motor spark coil, and an electrical resistor. To test their bond, a man and a woman would grip electrodes on either side of the Cupidoscope and move them toward one another until the woman felt a spark—not of attraction, but of electricity. The higher her tolerance for this mild current, the more of a love signal the meter registered. A needle decorated with hearts purported to show her devotion on a scale that ranged from “No hope” to “See preacher!”

It all sounds like a slightly painful party game—but the Cupidoscope was one experiment in a serious, decades-long quest to quantify love. This undertaking garnered the attention of leading scientists across the United States and in Europe in the early years of the 20th century, and it is memorialized most prominently in the penny arcade mainstay known as the Love Tester.

Possible Preaching Angle:

“How do you measure love?” The Bible gives an answer to this important question: It is measured by the self-sacrifice of the Cross—“By this we know love, that he laid down his life for us, and we ought to lay down our lives for the brothers” (1 John 3:16); “Then you, being rooted and grounded in love, will have power, together with all the saints, to comprehend the length and width and height and depth of the love of Christ, and to know this love that surpasses knowledge” (Eph. 3:17-19).