He started his career by proving a fundamentaltheorem in differential equations, developed practicalsolution methods for such equations, discovered a continuousspace-filling curve (then thought impossible), and laidthe foundations of abstract operator theory.
(Despite their being "obsoleted" by more general matrix and tensor methods,quaternions are still in wide engineering use because ofcertain practical advantages.)Hamilton once wrote:"On earth there is nothing great but man;in man there is nothing great but mind."
Grassmann was an exceptional polymath:the term is applied to two separate facts in the fields of opticsand linguistics, both discovered by Hermann Grassmann.
He also did important work in practical engineering, creating a methodfor accurate artillery fire during the First World War,and developing equations for radio and radar in preparation for the Second War.
Seki Takakazu (aka Shinsuke) was a self-taught prodigy whodeveloped a new notation for algebra, and made several discoveriesbefore Western mathematicians did; theseinclude determinants, the Newton-Raphson method,Newton's interpolation formula,Bernoulli numbers, discriminants, methods of calculus,and probably much that has been forgotten(Japanese schools practiced secrecy).
One of the more disturbing aspects of the unpopular war in Vietnam was the practice known as fragging. Disenchanted soldiers in Vietnam sometimes used fragmentation grenades, popularly known as frags, or other explosives to threaten or kill officers and NCOs they disliked. The full extent of the problem will never be known; but it increased sharply in 1969, 1970, and 1971, when the morale of the troops declined in step with the American role in the fighting. A total of 730 well-documented cases involving 83 deaths have come to light. There were doubtless others and probably some instances of fragging that were privately motivated acts of anger that had nothing to do with the war. Nonetheless, fragging was symptomatic of an Army in turmoil.
will never discover any inventions morebeautiful, more simple or more practical than those of nature."
The European Renaissance developed in 15th-centuryItaly, with the blossoming of great art, andas scholars read books by great Islamic scientists like Alhazen.