生平

American industrialist and inventor who established Colt's Patent Fire-Arms Manufacturing Company and made the mass production of revolvers commercially viable

Tenth president of the United States known for his advocacy of states' rights and his unique rise to the presidency following the death of William Henry Harrison

American naturalist, essayist, poet, and philosopher known for "Walden" and "Civil Disobedience", advocating simple living and citizen defiance

Eighth president of the United States and co-founder of the Democratic Party

French physicist, astronomer, and mathematician who co-discovered the Biot–Savart law, established the reality of meteorites, made an early balloon flight, and extensively studied the polarization of light