1921

Francis Okie works with 3M to create Wetordry™ Waterproof Garnet Paper, the first water-resistant sandpaper.

While sanding, a user could use water or oil to reduce dust and friction. It revolutionizes the sandpaper industry.

A University of California student, John Larson, invents the polygraph – or “lie detector” – machine.

Police begin to use it for interrogations in 1924.