Method for manufacturing glass, method for manufacturing lens, and melting apparatus

A method for manufacturing glass, comprising the steps of:

• heat-melting a raw material for producing glass by using a melting furnace having a plurality of gas flow paths while the raw material is levitated from the melting furnace by a gas ejected from the gas flow paths;
• and
• performing cooling so as to produce glass,
• wherein the melting furnace includes a recess portion,
• the melting furnace has at least one first gas flow path configured to eject the gas in the vertical direction into the recess portion,
• the melting furnace has a plurality of second gas flow paths configured to eject the gas in the direction toward the center axis of the melting furnace into the recess portion,
• wherein the plurality of second gas flow paths are disposed on the circumference of a plurality of circles centering on the center axis extending in the vertical direction of the furnace, the circles being positioned at a plurality of heights from the center of the recess portion,
• the raw material is heat-melted while the raw material is levitated by the gas ejected from the first gas flow path of the melting furnace and the gas ejected from the second gas flow paths of the melting furnace, so as to produce and maintain an orbital motion, of the raw material, about the center axis of the furnace as processing proceeds, and
• the molten raw material is cooled so as to produce glass.