Which German engineer, a rival of Karl Benz, built a four-wheeled motor car in 1886?

Which American poet, who lived from 1885 to 1972, shares his last name with a unit of weight? Which president, who died in 1885, insisted on a burial place where his wife could one day lie beside him? Who reportedly spoke his last word, "Water", in July 1885? Alfonso XIII was king of which country from 1886 to 1931? The 1887 Michelson-Morley experiment demolished the idea of which medium that supposedly carried light waves? Which 1888 Rudyard Kipling story is about two adventurers who become kings in Kafiristan? Who reigned as King of Prussia and German emperor from 1888 to 1918? Which 1889 Mark Twain novel sends a 19th-century American back to Camelot?