Henry's cross section actually shows a double action revolver. Below is a single action revolver. While related, they are two different animals.
Sorry I couldn't find a better diagram. I would have thought that finding a cross section or cutaway side view would have been a piece of cake, but it proved to be anything but. Hopefully this illustrates a single action well enough to provide some idea how they work, and why Mr. Baldwin's lies were so obvious to those of us familiar with these guns.
If that won't do it, maybe an animation found on YouTube might: