August 12

August 12 is the 225th day of the year, and the American record for it runs from 1834 to 1994 — a span of 160 years. The entry that anchors it: An official administrative history of the Manhattan Project, 1945.

Through the nineteenth century the date gathered the tensions that would define the era. In 1834, a race riot in Philadelphia, United States, destroyed African-American businesses and killed two people.

In the decades after the Civil War, the date marked a country remaking itself. In 1881, Franco-American children as young as seven years old began striking against Cabot Mill in Brunswick, Maine, shutting down operations for three days. Then, in 1898, the Hawaiian flag is lowered from ʻIolani Palace in an elaborate annexation ceremony and replaced with the flag of the United States to signify the transfer of sovereignty from the Republic of Hawaii to the United States where it is formally recognized as Hawaii.

As the country moved into the modern age, the date accumulated new kinds of firsts. In 1945, an official administrative history of the Manhattan Project, written by American physicist Henry DeWolf Smyth, was released to the public days after the atomic bombings of Hiroshima and Nagasaki.

In the postwar decades the date belonged to a nation of enormous reach and unfinished arguments. In 1960, Echo 1A, NASA's first successful communications satellite, is launched.

In living memory, the date has kept adding to the record. In 1990, near Faith, South Dakota, American paleontologist Sue Hendrickson found one of the most complete Tyrannosaurus rex skeletons, nicknamed Sue. Two years on, in 1992, Canada, Mexico and the United States announce completion of negotiations for the North American Free Trade Agreement (NAFTA) Two years on, in 1994, Major League Baseball players go on strike, eventually forcing the cancellation of the 1994 World Series.

The date is also a birthday. Among the Americans born on August 12: William P. Sanders (1833), American army officer; Michael J. McGivney (1852), American priest and founder of the Knights of Columbus; Diamond Jim Brady (1856), American businessman and philanthropist; Katharine Lee Bates (1859), American poet and author; and Edith Hamilton (1867), German-American author and educator.

August 12 is also a date of endings. Among the Americans who died on it: Albert Gallatin (1849), Swiss-American ethnologist, linguist, and politician, 4th United States Secretary of the Treasury; Eliphalet Remington (1861), American inventor and businessman, founded Remington Arms; James Russell Lowell (1891), American poet and critic; and Thomas Chamberlain (1896), American colonel.

Taken together, the 8 entries on August 12 span 160 years of American life. A date is an arbitrary container, but what fills it is not arbitrary at all.