If you ever see one of these things you should buy it . I they were used to hang carbon arc lamps from the ceilings in buildings and sheltered locations . Known as "ceiling boards", these were produced by many manufacturers from the 1880's to the 1910's but they are today quite scarce. Anyone interested in arc lamps will buy them as they are the ideal thing to display a lamp with. Here is more info on these...[id=647900868]