A magical find on one of my trips to the Elephant Trunk flea market included twenty-five or so glass lantern slides created by the Keystone View Company. A little reading (Wikipedia) revealed that the Keystone View Company, located in Meadville, Pennsylvannia, was a major distributor of stereographic images.
In 1905 they began its Educational Department, selling views and glass lantern slides (the 4 x 3.25 inch ancestors of the better-known 2 x 2 inch slides containing transparencies on film, which eventually replaced them) to schools throughout the country. Up until 1963 hundreds of educational sets were marketed to teach geography, social studies, science, history and reading.
The slides show children and adults, at play and at work, from all over the world. And each slide has an accompanying card that tells the viewer about the people within the photograph. I'll post the other slides when I have finished cleaning and photographing them, but I really wanted to pay my respects to the staff photographers at KVC, whoever you may be, for their wonderful photographs, which brought a truly beautiful perspective of the world into the classroom.