By 1851, which American photographer's failing eyesight had begun to hamper his work?

By 1812 there were 11,000 of which Frenchman's looms in use in France alone? By 1825 Spain had lost all its American colonies except which two islands, lost in 1898? By 1845, the price of which animal pelts had plunged as silk replaced them in men's hats? Which New York jeweler, with partners John Young and J.L. Ellis, switched from selling paste jewels to real gems in the… By 1857, who was producing 10,000 steel plows a year? By 1871, which was the largest kingdom in the German Empire? By 1877, which author had his idea for a story in which Edward VI and a poor boy change places? By 1880, both Edison and British physicist Joseph Swan had applied for patents on which type of electric lamp?