The Cincinnati Red Stockings introduce knickerbocker trousers. [1.17]

The ball is required to weigh not less than 5 and not more than 5 1/4 ounces, with a circumference of not less than 9 and not more than 9 1/4 inches. [1.09]

The umpire says, "Play" for the first time. [4.15A]

A time at bat is not charged to a batter who walks. [10.16]

Canvas-covered bases are required. They are fifteen inches square, the same as today. [1.06]

An umpire’s fees and expenses are paid by the visiting club.

An umpire is given the power to impose fines–of not less than ten dollars and not more than twenty dollars–when he thinks it’s necessary.

An umpire may terminate a game after a rain delay of thirty minutes. [4.12]

The pitcher is required to face the batter when he pitches. [8.01]

All pitched balls must be called strikes, balls, or fouls.

The number of strikes in an out is officially three. [6.05]

The catcher is required to catch a third strike on the fly. [6.05]

The base on balls decreases to eight. [6.08A]

The pitching distance is lengthened to fifty feet. [1.07]

The pitcher is fined for deliberately hitting a batter with the ball.

A spectator who "hisses or hoots" at or insults the umpire may be ejected from the grounds. [9.01E]

Umpires may not reverse decisions on matters of judgment. [9.02]

Umpires may not confer with spectators or players. [General Instructions to Umpires]

If an umpire imposes a fine or declares a forfeit, he must report it to the league secretary within twenty-four hours. [4.18]

Umpire corruption rears its ugly head for the first and only time: a National League umpire, Richard Higham, is expelled from the league for collusion with gamblers.

The first system of salaried umpires is introduced, under the same system that is in use today. The four men hired came from cities not represented in the league. [9.01]

An error is charged to the pitcher for a base on balls, wild pitch, hit batter, and balk. [10.13]

The bat may have one flattened side. (This rule lasted only one year.) [1.10]

The pitcher’s box becomes four feet by seven feet. [1.07]

An umpire may introduce a new ball at any time. Before this year, when a ball was lost, the umpire gave the team five minutes to find it before he threw in a new one. An umpire must have two baseballs at his disposal at all times. [3.01]

First and third base are moved within the foul lines.

A hit batsman is not charged with a time at bat. [10.02]

A pitcher must keep one foot on the rear line of the box and may not take more than one step in delivering the ball. Before delivery he must hold the ball in front of him so that it is visible to the umpire. [8.01]

No error is charged to the pitcher for a base on balls, wild pitch, hit batter, and balk. [10.13]

The umpire may call a game if the spectators are disorderly. The maximum fine for arguing with an ump or protesting a call is ten dollars.

The batter is no longer allowed to request a high or low pitch.

A batter hit by a pitched ball is entitled to first base and not charged with a time at bat. [6.08b]

A strike-out is called on four strikes. (This rule lasted only one season.) [6.05]

Home plate is to be made of rubber and is to be twelve inches square. [1.05]

If a runner is hit by a batted ball, the batter is credited with a hit. [10.05]

The strikeout is back to three strikes. [6.05]

It is a ground-rule double instead of a home run if the ball is batted over the fence in fair territory where the fence is less than 210 feet from home plate. [6.09]

The mandatory fine for a coach who leaves the coach’s box to protest a call is $5.

An error is charged to the pitcher for a base on balls, wild pitch, hit batter, and balk. [10.13]

A hit batsman is awarded first base and credited with a hit. [6.08]

The sacrifice bunt is statistically recognized, but the batter is charged with a time at bat. [10.09]

The pitching distance is increased to sixty feet, six inches, where it remains today. [1.07]

The pitcher’s box disappears (never to be seen again) and is replaced by the rubber–a slab twelve inches long and four inches wide. [1.07]

The maximum diameter of the bat is increased to 2 3/4 inches, where it remains today. [1.10]

The infield fly rule is adopted: the umpire may call an infield fly when there is one out and first and second or first, second, and third base are occupied. [6.05E]

A strike is charged to a batter for a foul tip. [6.05A]

The limits on fines change again–to not less than $25 and not more than $100.