It's a "bi-chain" with two sprockets each side giving four gears or eight, I think there are two chainrings each side, - one of Velocio's own builds about 1909/10.
Only info I can find is from The Golden Age of Handbuilt Bicycles by Jan Heine and Jean-Pierre Praderes, beautifully illustrated with other early innovations as well.
It's a "bi-chain" with two sprockets each side giving four gears or eight, I think there are two chainrings each side, - one of Velocio's own builds about 1909/10.