will be seen that the core c of the jet causes the induction of currents of air indicated by the lines a the amount of air so induced progressively increased along the path of the jet when the body of the jet i e the gas of the core intermixed with the induced air reaches the boundary of the blast a zone of interaction is established in the region indicated by cross lining marked i in fig2 as the stream s of molten glass descends and approaches the jet delivered from the orifice 7 the currents of air induced by the action of the jet cause the stream of glass to deflect toward the jet core as indicated at 10 although the glass orifice 3 may be of substantially larger diameter or cross section than the jet orifice 7 the gravity feed of the glass stream s results in substantial reduction in diameter of the glass stream so that when the stream meets the jet the diameter of the stream is much smaller than the diameter of the glass orifice with the higher velocity of the jet as compared with that of glass stream even when the glass stream meets the jet in the upstream region adjacent the jet core the glass stream will not.