In the early 1800s and even through to the 1900s, if you wanted to alter your photo to create an illusion it was an incredibly labor intensive process. There was combination printing, photomontages and even overpainting. They all took lots of time and all had significant drawbacks.
These photos were created during an era where they genuinely had to be measured and consider how you were adapting the film negative itself. There was no magical undo button, just lots of trial and error, and still yet, its amazing what a little "magic" can do isn"t it?
Fantastic photo manipulations performed before the golden age of photoshop. Believe nothing you see!