Abstract: Forehearth constructions are described in which means are provided to heat the sides of the stream of molten glass (27) passing along the forehearth from a glass-making furnace to one or more molten glass outlets by way of flames emerging from a series of substantially horizontal slots. The slots are located in the side walls of the channel above the level of the molten glass surface when the forehearth is operating, and the ribbon of flame provides improved heat transfer to the molten glass stream. Burner blocks are disclosed for use in constructing a forehearth of this type, each consisting of a block of refractory material having an internal cavity (3) of generally wedge-shaped construction and having an elongated outlet in. the form of a slot (4) in the face of the block. A combustible gaseous mixture, or the components to form a combustible gaseous mixture, are fed into the cavity remote from the slot.