Michael Sokolski, the inventor of the Scantron, died recently and news of his death reminded me of this invention from 1935. Rather than use a number 2 pencil, students punched holes into a multiple choice test and weights were dropped over their test where the correct answers were supposed to be. The weights that fell through the holes, indicating a correct answer, were then weighed and the number of correct answers was determined.
From the September 1935 issue of Popular Science:
EXAM PAPERS ARE GRADED BY WEIGHT
Student's examination papers are being graded with a weighing machine at a Kentucky teachers' college, where the new method has been found speedy and accurate. Each student receives a card bearing "true-or-false" and similar questions, and punches holes as indicated points to record his answers. When the card is placed in the weighing machine, small weights drop through the holes correctly punched and fall to a platter, where the total weight gives the score.
Illustrations for U.S. patent number 2,033,817 appear below.