The answers had to be searched for by hand, and that could take weeks. The index card system was developed in 1903 by Otlet, seen here in the same year.
The answers had to be searched for by hand, and that could take weeks. The index card system was developed in 1903 by Otlet, seen here in the same year.
Photo Gallery: The Forgotten Visionary
Spiegel Online
http://www.spiegel.de/fotostrecke/photo-gallery-the-forgotten-visionary-fotostrecke-70716-6.html