You are looking at the well known Super Champion (Osgear) with the wrong tension roller, and probably the wrong tension arm. Absolutely the opposite to indexed.
These were used late 1930's to about 1950. To change gear the lever was moved as far past the next position as necessary, and you sometimes got the next gear. You will see the very short cable movment is also against it. Superceded when it was realised that the chain needs to be fed on to the cogs in line. Killed off by the Simplex TdF.
I have ridden road races with these and the Campagnolo Paris Roubaix back pedal change.