Taylor was optical manager at Cooke, not a man named Cooke. Three air-spaced elements, plus–minus–plus, were enough to flatten the field and hold colour for a photographic plate. The 1893 patent became a family tree: Tessar, many enlarging lenses, cheap camera triplets.
Air between the glasses is the point. You can see the three pieces on this board and the focus on the meter. It is slower to assemble than a cemented pill and much easier to describe.