"The planet's immune system is doing everything it can. The planet's immune system is doing everything it can."
- Kurt Vonnegut, Jr.

Modern Mechanix offered delighted robotics enthusiasts with this story in 1934; as you see, the robot is a wily server of tennis balls, if not a returner of tennis balls.

(Actual tennis robot circa 1934)

PITTING their skill against the strokes of a mechanical tennis player in a recent exhibition, St. Louis racquet stars found themselves deluged by a barrage of deceptive lobs and smashing serves which drove them to the base line and forced them to net several of their returns.

The invention of Edward Serrano, winner of the St. Louis district doubles crown in 1932, the robot will do practically anything the human tennis player can do except return the ball. Mounted on a movable, two-wheeled frame, the iron body of the machine is crowned by a bucket-like head which contains sixty balls. A striking bat, powered by a small electric motor, serves, lobs or drives the balls as they are fed automatically from the hopper into a dish-like receptacle.

(Inventor and tennis robot circa 1934)

Various adjustments permit a wide latitude of strokes. Hitting toward the top of the striking surface results in a top-spin drive; hitting toward the bottom produces an under-cut stroke. When the robot is called upon to lob it is adjusted backward until its “head” forms an acute angle with the ground, much like the wartime trench mortars. The serve is executed merely by slowing up the drive.