The Museum’s Guggenheim Hall of Minerals includes this touchable rock crystal quartz specimen, found in Hot Springs, Arkansas. On the Mohs Scale of Hardness, which measures the degree of resistance offered by a mineral’s surface to being scratched, quartz ranks 7 while soft talc has a value of 1 and diamond—among the hardest minerals—10.
One century ago, San Francisco’s 1915 World’s Fair closed its doors, ending one of the most unique events in American history. For 288 days, the fair brought together an odd array of individuals that seemingly belong in different chapters of the history textbook. Civil War veterans could watch as Henry Ford produced a car every ten minutes on his assembly line. Original miner 49ers could traverse a fake mine and see a glowing, radioactive mineral called radium. Patty Reed, a surviving member of the infamous Donner party, could walk through General Electric’s model house and marvel at their flameless toaster. At a time when only 20 percent of Americans had electricity, fairgoers could pay to take an airplane ride or make a transcontinental phone call to New York. It was a moment of change, and a fair to remember.
The fair itself, also known as thePanama-Pacific International Exposition (PPIE), marked two monumental achievements. The first was the completion of the Panama Canal. The United States began construction on the canal in 1904 and finished in 1914. Dubbed “The 13th Labor of Hercules,” the canal shortened the shipping route from New York to San Francisco by 7,700 miles. The new sea route enhanced American business, and helped make San Francisco one of the world’s preeminent port cities.
The second achievement was the reconstruction of San Francisco. Less than a decade before, San Francisco was reduced to rubble by one of the worst natural disasters in modern history. The 1906 earthquake decimated the young city. Many believed the reconstruction could never restore San Francisco to its prior glory, or would at least take generations to complete. Less than a decade later, however, the rebuilt San Francisco hosted one of the largest gatherings of all time. Over the course of its 10-month span, nearly 19 million people attended the World’s Fair. At the time, California’s population was roughly 3.5 million.
The National Archives has photographic records from many of the world’s fairs. Few, however, are quite as striking as the colored lantern slides from the Panama Pacific International Exhibition. Lantern slides were a popular form of photography in the 19thand early 20th centuries. Photographers would often develop images onto light-sensitive lantern glass, cover the image with an additional layer of protective glass, and bind the two layers together with paper tape. In some instances, such as the examples in this blog, slides were hand-colored using oil paints, dyes, or pigments. The lantern slides could then be projected to a viewing audience, and were ideal for educational or professional settings.
Photograph of the Panama-Pacific International Exposition at Night, 1915. Local ID: 16-SFX-85.