Have you gone over them with a magnifying glass for any markings?

nziegler, looks like a couple of turn of the century (more like 1905) hanging oil lamps. These are sometimes called "Library Lamps." They were originally oil/kerosene burning (you put the oil into the glass font via the brass cap). The "bell" hanging at the top was to catch smoke from the burning wick and is called a smoke bell (how original.) The style is what is usually referred to as "Eastlake" here in the US. There are electrified burners that easily screw on to the font to make them electric rather than oil burning but be sure to wash out the font very very well. Old oil or kerosene is highly flammable. The sets of chains were typically attached to weights and pulleys which allowed the light to be raised and lowered to clean the burner and chimney or to refill the font.