Change of Pace (1867)

“They never discovered the change of pace which marked Martin’s pitching; but after judging the pace of a ball out of reach they would hit the next, in full expectation of it being sent in at the same speed, when, lo! and behold, it was either swifter or slower, and the result, of course, was that the ball was either hit foul or popped up for an easy catch.” “Mutual vs. Eclectic,” Brooklyn Union, June 20, 1867, p4

Previous earliest use (Dickson Baseball Dictionary, 3rd edition, 2009):
1867.  “J. Williams, the Capital pitcher, would occasionally drop a ball short, but the change from swift to slow was too apparent to be effective.  This style to work well must be done on the sly, the change of pace not being perceptible.” (Henry Chadwick, The Ball Players’ Chronicle, July 18; Peter Morris).