Using a newly designed apparatus, the U.S. Bureau of Standards workers are experimenting to determine the relative home-run qualities of American, National and International baseballs on February 21, 1938.
In conducting the tests, a scientist pulls the trigger of an air gun loaded with a wooden projectile representing the slugger’s bat. The projectile strikes a baseball causing it to fly toward a ballistic pendulum. After each of such hits, the scientist takes a reading on the pendulum. It tells him how hard the ball hit the pendulum, or whether it was a home-run, a double, or just a pop fly. Dr. H.L. Dryden, Chief Engineer Division of Mechanics and Sound, designed the machine and supervised the tests.