Obviously a very 9old lens indeed. Un-coated and still in surprisingly good condition. It's age is also give away with the 'waterhouse' stops instead of a variable iris. If there is no makers name on the lens this makes positive ID awkward to say the least but I would estimate it comes from around the 1880-1910 era, give or take a few years. It would probably cover the old half plate size 61./2 x 41/2 inches or even whole plate. I don't think there is any doubt about it, but you would probably find it rather 'soft. at anything except the smallest apperture.