By the early 1920s, the Société Pathé Frères had built the largest film equipment and production company in the world. To increase their 1922 Christmas sales, they released the first projector meant for home use: the Pathé Baby. Kodak quickly released its own brand of home equipment and film, which found greater popularity and by 1935 Pathé was forced into bankruptcy.
The 9.5 mm Pathé Baby films come in small cassettes holding approximately 30 feet of film that plays for around 60 seconds. What makes it unique is that it has sprocket holes down the center rather than on the sides. The film also has an ingenious little notch cut into each title frame that triggers the projector to stop for a few seconds, even though the operator continues to crank the film, allowing viewers time to read the text.
Princeton's collection of optical devices, and optical prints and photographs, is basically a pre-cinema collection. However, thanks to the help of Professor Rubén Gallo, we recently acquired a 1920s Pathé Baby projector along with approximately 1,000 Pathé films, including natural history, animation, biography, current events, and multi-reel comedies and dramas.
Here is a sample (black & white, no sound):
There is a group of enthusiasts based in the United Kingdom who still use 9.5 mm film. Their website is www.Pathescope.freeserve.co.uk/Pathe95.htm