1846
Mexican-American War Declared
After a skirmish on the disputed Rio Grande that Polk called an unprovoked attack, Congress declared war. Henry David Thoreau refused to pay his taxes and went to jail. Abraham Lincoln, a freshman congressman, demanded to know the exact spot where Americans had been killed. The war lasted twenty-one months and took half of Mexico.
Corn Laws Repealed
Prime Minister Peel, confronted with Irish famine, split his own Tory party to repeal the protective tariffs that kept cheap foreign grain out of Britain. It was the triumph of Manchester-school free trade - and the making of the Liberal Party. Peel lost his office. The principle stood for seventy years.
Neptune Discovered
After Le Verrier in Paris calculated where an unseen planet should be from Uranus's wobbles, a young German astronomer named Galle pointed a Berlin telescope at the spot and found it on the first try. Newton's law of gravitation, applied at the tip of a pencil, had conjured a new world out of mathematics.
Iowa Joins Union
Carved out of the Louisiana Purchase, Iowa entered the Union as the twenty-ninth state and as a free state to balance slave-state Florida. The Missouri Compromise line still held, barely. Settlers poured in, German and Irish and Yankee, to break the tallgrass prairie under John Deere's steel-bladed plow. Within a decade Iowa's black soil would make it one of the richest agricultural regions on the planet.