The US Army launched the K-9 corps. (1942) The newly established War Dog program, also known as the K-9 corps, was an instant hit, and over one million dogs served on both sides in World War II. The most decorated dog of the war was Chips, a dog who attacked a machine gun nest single-handed and forced the entire nest to surrender.
Czar Alexander II was assassinated. (1881) Alexander had actually been a very progressive ruler for his time, and was even in the process of reforming the Russian political system. He was eventually assassinated by the "People's Will" group, leading to huge setbacks in the creation of the Duma, or Russian parliamentary system.
The Confederate States of America approved the use of African-American soldiers. (1865) The idea had been proposed several times over the course of the war, but Confederate higher-ups were reluctant, since it would essentially be freeing the slaves. When the proposal finally passed, it did not stipulate that the slaves were to be freed, though Robert E. Lee did request it.
The Senate began to hear impeachment charges against Andrew Johnson. (1868) The charges included everything from violating congressional Reconstruction acts to engaging in "inflammatory and scandalous harangues." Johnson faced eleven charges; to put that in perspective, Clinton faced only two in his impeachment trials.
The character of Uncle Sam had his print debut. (1852) The famous caricature first appeared in the New York Lantern, a weekly comic. Though the idea of Uncle Sam had been used on and off in popular culture, the figure had its first nation-wide debut in print on this day.
Mongolia declared independence from China. (1921) The country was led by Russian mystic Ungern von Sternberg, who believed himself to be a reincarnation of Genghis Khan. He was captured and executed less than a year later, though Mongolia remained independent.
Uranus was discovered. (1781) German-born astronomer William Herschel discovered Uranus, the first planet to be discovered in modern times. Though others had seen the planet before, they had classified it as a star, a misconception that Herschel corrected.
The Butler Act was signed, prohibiting the teaching of evolution in Tennessee. (1925) The law went into effect a few weeks later, setting the stage for the infamous Scopes Monkey Trials.
CBS World News Roundup premiered. (1938) The radio program was originally intended to be a one-off to report on the occupation of Austria, but became very popular, since it was the first program to feature live correspondents in Europe reporting back to New York. It continued to air through the 21st century.
New College in Massachusetts renamed itself Harvard College. (1639) The now famous university was originally named New College, but was renamed Harvard after a clergyman named John Harvard bequeathed a substantial sum of money to it in his will. In its early days, Harvard had only about 30 students.