In size and shape, Hollerith’s invention resembled a cross between a bookshelf and a grand piano – a grand piano you could feed punchcards for calculation. Hollerith designed it for a Census Bureau competition, as a practical aide for their tabulations – for the first time since a census began, the bureau was taking in more data than it could process manually. In a competitive field test from four districts around St. Louis, Missouri, his machine took 72 hours to absorb all the data, compared to more than 100 hours for his competitors. When it came time to tabulate the data, Hollerith took just 5.5 hours, compared to around 45 or 55 for his competitors. Word of his amazing feat spread quickly through government circles.

On this day, December 9, in 1888, the same year the census was held, Herman Hollerith installed his tabulating machine at the War Department, to help their record keeping and calculations.

Hollerith planned on exhibiting his machine in Paris the following year and attempted to secure from the War Department a recommendation – “some statement in the nature of a certificate, regarding the operation and use of this system… so that I could use the same in connection with my exhibit in Paris.” The government demurred, but the machines proved popular enough in Paris to get Hollerith several more orders. Two of the machines still remain in existence: one at the Smithsonian Museum, and one at IBM headquarters.