This was a period when the question of whether the curve ball actually curved was hotly debated. Among the true believers was St. Louis Cardinals pitcher Dizzy Dean. "Ball can't curve?" he famously declared during the 1930s. "Shucks, get behind a tree and I'll hit you with an optical illusion." But anecdotes aren't a substitute for scientific data. So once Briggs officially retired, he decided to do the experiments to settle the matter. And he was well-connected enough to enlist the aid of the pitching staff of the Washington Senators and their manager, Cookie Lavagetto, to do so. It wasn't just a question of baseball, either: the question related to NIST's ongoing research into ballistics and projectiles: the rate of spin is related to how much the ball (or projectile) is deflected at different speeds. Apparently the NSB (now NIST) conducted lots of experiments with golf balls and baseballs; one of Briggs' publications was a 1945 paper entitled, "Methods for Measuring the Coefficient of Restitution and the Spin of the Ball."
Read how Briggs designed experiments to find out exactly how much of a curve there is to a curveball at Cocktail Physics. Link