Stirring of molten glass

In a glass melting furnace, a stirrer for stirring molten glass, which stirrer comprises a stirring member for immersion in the molten glass, a rotary shaft extending upwardly from the stirring member to a roof of the furnace, the shaft being rotatably mounted and connected to a drive device arranged to rotate the stirrer, a stationary hollow casing formed of a material which contains a high percentage of platinum surrounding the rotary shaft in spaced relationship thereto, the casing extending downwardly from the roof of the furnace, terminating above the stirring member, and being separate therefrom, and separate inlet and outlet means in the casing for introducing and removing a flow of inert gas through the space between the casing and the shaft whereby the atmosphere between the shaft and the casing may be different from the atmosphere above the molten glass in the remainder of the furnace, the shaft and stirring member being formed of a material resistant to attack by molten glass and different from the material of the hollow casing.