Changes

* '''19''' - Captain Albert Ball, [[VC]], MC, DSO & 2 bars, commences his career as a fighter pilot. By the time he is killed, aged 20, in 1917, he has become one of the [[First World War]]'s greatest air aces, accounting for at least 44 [[German]] aircraft.

* '''19''' - Captain Albert Ball, [[VC]], MC, DSO & 2 bars, commences his career as a fighter pilot. By the time he is killed, aged 20, in 1917, he has become one of the [[First World War]]'s greatest air aces, accounting for at least 44 [[German]] aircraft.

* '''19''' - was the average age of front-line [[US]] service personnel fighting to defend democracy in [[Indochina]] during the [[Vietnam War]]  

* '''19''' - was the average age of front-line [[US]] service personnel fighting to defend democracy in [[Indochina]] during the [[Vietnam War]]  

* '''19''' - [[Evariste Galois]] develops [[group theory]], and wrote it out completely on the eve of his death at age 20; it took old [[mathematicians] a century to comprehend it

* '''19''' - [[Evariste Galois]] develops [[group theory]], and wrote it out completely on the eve of his death at age 20; it took old [[mathematicians]] a century to comprehend it

* '''20''' - Carl Friedrich Gauss makes his first mathematical discoveries, which will lead to the completion of "Disquisitiones Arithmeticae", his magnum opus, at the age of 21.

* '''20''' - Carl Friedrich Gauss makes his first mathematical discoveries, which will lead to the completion of "Disquisitiones Arithmeticae", his magnum opus, at the age of 21.