A high-refractivity low-dispersion optical glass that gives press-molding preforms excellent in high-temperature shapability and suitable for precision press-molding, including an optical glass comprising B2O3, La2O3, Gd2O3 and ZnO as essential components, substantially containing none of lead and fluorine, having a refractive index of 1. Dynamic \u201cWeb Components\u201d are used to automatically customize web pages. A catalyst supply container connected with the reaction chamber is so arranged that the catalyst material is automatically added from the supply container to the reaction chamber.