Hi Ellen,(posted 8906 days ago)I'm sad to say that #122 film is impossible to get to my knowledge. The only place that it was available from now carries #127 & #620 only as of about 6 months'!
There is a page that describes your camera elsewhere on this site but I've copied it here for you:
No. 3A Folding Autographic Brownie
Type: Folding rollfim Introduced: July 1916 Discontinued: Nov 1926 Film size: 122 Picture size: 3 1/4 X 5 1/2" Manufactured: US Lenses: Achromatic and Rapid Rectilinear - see below Shutters: Ball Bearing or Kodex - see below Numbers made: ? but 70,000 before 1921 Original price: ?
Description: Imitation leather covering; reversible reflecting finder; sliding focusing with lock; from serial number 1001.
Variations: Achromatic lens: Jul 1916-25: ball bearing shutter; 1925-Nov 1926: Kodex shutter
Rapid Rectilinear lens: July 1916-25: ball bearing shutter; 1925: Kodex shutter
Kodar f/7.9 lens: May 1925-26: Kodex shutter
Approximate worth: $10-20
I believe yours was manufactured between 1917-25 because of the ball bearing shutter and the patent date.
Sorry about the film!
Chuck Baker The Brownie Camera Page