This design for a sideboard appeared in Thomas Sheraton’s The Cabinet-Maker and Upholsterer’s Drawing-Book (1793).
The explanation includes: “The sideboard has a brass rod to it, which is used to set large dishes against, and to support a couple of candle or lamp branches in the middle, which, when lighted give a very brilliant effect to the silver ware. The branches are each of them fixed in one socket, which slides up and down on the same rod to any height, and fixed any where by turning a screw. These roads have sometimes returns at each end of the sideboard; and sometimes they are made straight, the whole length of the sideboard, and have a narrow shelf in the middle, made of full half-inch mahogany, for the purpose of setting smaller dishes on, and sometimes small silver ware.”
The description also explains that commonly in large, circular sideboards, the left hand drawer can be fitted as a plate warmer. This is accomplished by having a rack in the middle for the plates, lining the box with “strong tin” and a partially open design to fit a small heater contraption.