a dead ball. One New York firm, in an effort to find favor with good fielding teams, claimed in an advertisement that "our professional dead balls... are made of all yarn without rubber and are the deadest balls made."
Even at that early date, however, most baseballs were made of the same general ingredients as today go into the making of baseballs—rubber cores surrounded by tightly wound woolen yarn and covered with leather.
When the National League came into being in 1876 professional baseball reached "major league" stature for the first time. The rules concerning baseballs became more exacting and as a result the baseballs, particularly those used in the National League, and later in the American Association and American League, became more uniform.
An important change in the composition of the baseball was made in 1910 with the introduction of the cork center. The idea of a cork center has been traced back to 1863 when an Englishman by the name of Weeks patented a cork-center ball for cricket. The cork center was first used in baseballs about 1900, but this new construction was not satisfactory at first because the wool yarn swelled after the ball was made. This was eliminated by reducing the size of the cork center and putting a layer of rubber around it.
With the introduction of the cork-center baseball in 1910 pitchers soon began to develop freak deliveries—shine ball, spitball, emery ball, etc.—to offset the "lively" ball. Drastic changes were made in the rules in 1920 to outlaw these pitches. However, recognized "spitball" pitchers, 17 in all, were permitted to continue using their specialty for the remainder of their careers. Most successful of these, and the last to close his major league career, was Burleigh Grimes, who pitched last for the Yankees in 1934.
In 1931 the center of the ball was again changed when the cushioned cork center made its bow. The cushioned cork center, still in use, consists of a small sphere of composition cork which is molded to a layer of rubber. The first layer of black rubber is made up of two hemispheric shells. The two openings where these shells meet are sealed with a cushion of red rubber
