No. 2 Brownie
The Model D has a wood and jute board body covered with leathette, a simple meniscus lens (about 4-1/2" focal length), three aperture stops (about f/16, f/22 and f/32) and a rotary shutter (instantaneous or time). The instantaneous shutter speed is in the neighborhood of 1/25 to 1/50 of a second. The shutter has a flip-flop action. Pushing the shutter lever down would make an exposure and pulling it back up would make another exposure. Hopefully you advanced the film between flips and flops. There was no double exposure prevention. Ordinary daylight pictures with the relatively slow film of the 1918 era would be taken with the f/16 stop. The fixed focus lens produces a clear picture of subjects 8 ft. or more distant. There are two reflecting finders for pictures in either a vertical or horizontal orientation. A reflecting finder has a small lens and a mirror that projects an image of the scene onto a ground glass viewing screen. The image is upright but reversed and a little dim.
The Brownie is such a simple camera that this one still works after 100 years. The list price in the 1918 catalog was $2.75, or about $60 in depreciated 2019 dollars. A roll of No. 120 Kodak Non-Curling film for 6 pictures was 20 cents. Modern 120 film with eight 2-1/4"x3-1/4" pictures per roll will work in this Brownie. Size 120 film is readily available today from Kodak and other makers.
One odd bit of history is that the design of the lens on a No. 2 Brownie is older than photography. The English chemist and physicist William Hyde Wollaston devised the Wollaston Landscape Lens for use in an artist's camera obscura in 1812. The landscape lens had a positive meniscus lens with the concave face toward the subject and an aperture stop in front of the lens, exactly the same as in a No. 2 Brownie. The advantage of this design was that it gave a fairly wide clear field of view compared to an ordinary lens.
Battle of Nashville Monument Park
A sample picture on Ilford Ortho Plus film. I used an orthochromatic film that is relatively insensitive to red light to get a look like the old Kodak N.C. film, also an orthochromatic film, that was available when this camera was made.