Francis H. "Silk" O'Loughlin (August 15, 1872 - December 20, 1918) was an American umpire in Major League Baseball who worked in the American League from 1902 to 1918. He umpired in the World Series in 1906, 1909, 1912, 1915 and 1917, serving as crew chief for the last Series.
Born in Rochester, New York, O'Loughlin was one of six children. His father died when he was five years old. He entered baseball with the help of pitcher Stump Wiedman, a relative, and umpired in the New York, Atlantic and Eastern Leagues from 1898 to 1901. O'Loughlin may have acquired his nickname as a child when neighbors commented on the fine quality of his hair. However, at least one source describes the nickname coming much later when players saw him wearing a silk hat.
Silk came to the American League in 1902. He brought a unique style with him, originating the loud exclamations signaling balls, strikes and outs. Previously, umpires had simply informed the catcher or nearest defensive player of their calls. He was particularly known for his booming call of "ball tuh" and his drawn-out strike calls, as well as his snappy calls of foul balls. A 1909 New York Times article criticized the quiet work of umpire Billy Evans, saying, "Though they laugh at Silk O’Loughlin, everybody knows just what he says." Years later, Evans himself would remark, "Silk was a bundle of nerves. From the start of the game until the finish he was on edge. Baseball was a serious proposition for him."
Perceptions differ as to O'Loughlin's tolerance for disagreements. In 1911 he said, "I wouldn't give a snap for a player who wouldn't kick if he honestly thought he was right. Umpires have to stand the brunt of kicks, but if the player is one of the kind who is always thinking of winning and makes his kick and walks away, I don't mind it." However, the following year Christy Mathewson wrote that O'Loughlin was "the autocrat of baseball" and that he "refuses to let the players discuss a decision with him, maintaining that there is never any room for argument. If a man makes any talk with him, it is quick to the shower bath." Silk agreed with at least part of that statement. He was frequently quoted as saying, "A man is always out or safe, or it is a ball or a strike, and the umpire, if he is a good man and knows his business, is always right."