This is the original patent issued to Owens Corning in 1940 for what is known as Fiberglass, this patent has saved trillions in energy costs. Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from molten glass in which the resultant product consists of different sorts of glass or is characterised by shape, e.g. hollow fibres, undulated fibres, fibres presenting a rough surface.