Suspension chandeliers were designed to provide light by burning oil.  A wick would draw the oil (kerosene, whale or paraffin) and burn it.  These fixtures might have one central burning area or multiple arms holding oil fonts.  Some were designed to be lowered from the ceiling to provide more specific ambient light in a room.   The dome on a suspension chandelier aided in directing light evenly to the space below.  If the dome were made of reflective material, light would be scattered. With the advent of electricity in the late 1800s, they became less needed but are still lovely, large chandeliers that make a decided statement in today’s homes.